Ford Bronco And F-150 Links - Oil Pressure & Sender

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FORD BRONCO -> INSTRUMENTATION & WARNING; gauges, speedometer, PSOM, TSBs... -> Dash - A Pillar, Dash, Gauges, PSOM, Speedometer, TSBs -> Instrument Panel; Gauges, Speedometer, PSOM, etc. -> Gauges & Warning Lights -> Oil Pressure & Sender

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This is a Ford Bronco, Truck & Van Technical & Parts LINKS site developed by the MIESK5 Family & is not affiliated with the Ford Motor Co. in any manner.
Although we initially developed this site for 78-96 Big Broncos, information in many Links also applies to F, E Series & Cars. UPDATE; all Links via web.archive may be down; Copy orig. URL & go to http://replay.waybackmachine.org/ to search for the new archived copy

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Fake Oil Pressure Gauge TSB 88-05-14 for 87-88 Bronco & F Series

Instrument Custer Warning Light(s) May be dimly Lit or there may be a Malfunction of the four Pin Low Oil Relay on Vehicles so Equipped. This could be due to the Ignition Switch; TSB for 83-91 Bronco, F Series, Aerostar, Ranger, Explorer & many others

Loss of Instrumentation (tach, fuel gauge, etc.); E4OD transmission control switch wiring may be misrouted causing a short in the steering column and a blown # 17 fuse for 92-96 in TSB 92-22-5 for 92 Bronco & all Light Trucks

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Bulb Part Numbers in 80-81; Turn Signal, 4x4 Indicator, Oil Pressure, Map/Dome, Tail/Stop/Turn
Source: by MIL1ION at 7879blueovalbronco.com

Circuit Operation 87-88 F Series & Bronco; "...In recent years, Ford Motor Company has been doing something I view as a bit sneaky. They have taken the oil pressure gauge and turned it into a glorified warning light. It says it's an oil pressure gauge, it looks like an oil pressure gauge, but in reality it is not. starting in 1986 a change was made on some models that altered the function of the oil pressure gauge as we knew it. The variable resistance sending unit was replaced with an open/closed switch and an in-line 20 ohm resistor was installed between the gauge and the switch. Anytime you have more than 4.5 psi of oil pressure, the switch closes, completing the circuit from the gauge (with the 20 ohm resistor in-line) to ground. This then results in a gauge that reads just above the middle. As you can see, there is no variation to the gauge needle in this circuit. It will either read no oil pressure or half-scale (normal oil pressure). On this style of gauge circuit, if the oil pressure gauge reads in the middle, it is telling you only one thing - you have more than 4.5 psi of oil pressure. How much more is anyone's guess at that point. When oil pressure drops below 4.5 psi, the gauge will return to 0 and alert the driver of a problem...Ford released a TSB (#88-5-14) for 1987-1988 F Series and Broncos that called for converting the variable resistive style oil pressure gauge circuit to the switch style circuit - if the customer complained of low or erratic oil pressure readings. The kit contains an oil pressure switch and an in-line 20 ohm resistor that is to be connected between the end of the existing sending unit signal wire and the new switch. The variable resistance oil pressure unit removed from the vehicle is then discarded. I want to point out some diagnostic problems that can arise from this circuit. First, if you are working on this switch style oil pressure circuit (with the in-line 20 ohm resistor) and install a variable resistive sending unit in place of the oil pressure switch, the result will be a gauge that reads lower than normal due to having two resistors in series, the fixed 20 ohm in-line resistor and the variable resistive sending unit. On the other hand, installing the open/closed switch on a vehicle that incorporates the conventional oil pressure gauge circuit will result in a pegged gauge needle after starting the engine. Sometimes you can tell that you need a switch instead of the variable resistive sending unit by the presence of the in-line resistor a few inches from the switch connector. This is not a good rule of thumb though, since many vehicles have the fixed resistor on the back of the cluster, and some of the digital dashes have that circuit built into the cluster. To determine what style circuit you have, simply ground the sending unit wire with the key on. If the gauge reads exactly half-scale, you can be fairly sure you need a switch-style sender. If you ground the sender wire and the gauge pegs, a variable resistor-style sender is needed..."
Source: by James M at asashop.org

Cluster Background Information for 1994-2004
Source: by accutach.com

Cluster Connector Location, Behind Instrument Panel Diagram in a 96, Page 1
Source: by Ford via Chilton

Cluster Removal in 92-96; but Kusscave's site is now down; see Steve83's or tomtoc's Links; One thAng is, Gauges/cluster need to be stored in vertical or face-up positions. do Not lay any gauge or cluster face down; it will leak the dampening fluid. You can pull the cluster out w/gauges, PSOM and replace the gauge w/out losing your odometer reading. I had my cluster out for a month..it'll hold the mileage indefinitely, make that forever. his # 10); I managed to lift the gauge cluster up and tilted it to disconnect the connector to PSOM, and other gauges... And, Re; "... This is the plastic housing that the little wire loop runs through. The black thumbwheel is threaded around the plastic housing. By spinning the thumbwheel, the housing will back down and out (with the wire loop). You want to spin the housing all the way down and clear... Be gentle with it; I used a small phillips screwdriver to un-hook it; didn't need to spin it; If the cable sheath is white, it's probably about to break no matter how careful you are. If it's black with mesh reinforcement, you almost can't break it..." Shift Indicator Adjustment in 92-96 Source: by Steve83 (Steve, That dirty old truck) at http://www.supermotors.net/vehicles/registry/media/434182 "...I always unhook the cable (shifting to L or 1 makes it easier), then spin the wheel. You can't really get to the indicator end to unhook it - I do it at the shifter (wheel) end. There's nothing inherently wrong with removing the wheel assy. But when you're trying to pull the cluster, it's easier to feed the bare cable end back around the column & thru the wiring harness..." miesk5 NOTE, Electronic modules, such as instrument clusters, powertrain controls and sound systems are sensitive to static electricity and can be damaged by static discharges which are below the levels that you can hear "snap'' or detect on your skin. A detectable snap or shock of static electricity is in the 3,000 volt range. Some of these modules can be damaged by a charge of as little as 100 volts. The following are some basic safeguards to avoid static electrical damage: Leave the replacement module in its original packing until you are ready to install it. Avoid touching the module connector pins. Avoid placing the module on a non-conductive surface. Use a commercially available static protection kit. These kits contain such things as grounding cords and conductive mats.
Source: by miesk5 at Ford Bronco Zone Forums

Cluster Replacement in a 96 from 1996 F-150, F-250, F-350, Bronco, F-Super Duty Motorhome Chassis Workshop Manual
Source: by Ford via thedieselstop.com

Cluster, w/Tach Pic, Back View w/Connector, Terminal & Bulb Identification in 87-91
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

Description & Operation, Diagnosis & Testing, Removal & Installation, Disassembly & Assembly, Cleaning & Inspection, Specifications & Special Service Tools/Equipment in a 96 from 1996 F-150, F-250, F-350, F-Super Duty and Bronco Workshop Manual
Source: by Ford via thedieselstop.com

Diaphram Leak Info & pic in an 83; "...As usual, the oil pressure sender diaphragm is leaking, causing the pressure to be equal on both sides. That makes the gauge read as if there's no pressure. It only takes about $12 & 10 minutes to swap it out..."
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

Erratic Gauges in 78-86; "... believe the 87 (88 for sure) and later Fords do not use an IVR. They use a system of small coils built into the gauge and depend on variable voltage sending units to function. Best indication of a bad IVR use to be the temp and fuel gauges performing radically at the same time since the constant voltage side of the gauges were receiving a wrong or intermittent voltage..."
Source: by Mulletwagon at fte

Erratic Gauges in 78-86; "...The cluster "Instrument Voltage Regulator (IVR)" is going bad, and staying on too long, sending too much current through the gauges & sensors. It has finally locked on, and is burning out your sensors every time you turn your key on. :( Remove the instrument cluster and then pop the VR off the film circuit - it's a metal box with 2 brass snaps. They're available at most parts stores for a few bucks. The hardest part will be getting the headlight & wiper knobs off, so post again if you need instructions on that.In this photo, counting from the RIGHT, it's between the 2nd & 3rd black bulb holders along the top of the cluster. You can see the hex screw holding the mounting tab, and just below that, you can see the 2 brass snap terminals..."
Source: by Steve83 (Steve, That dirty old truck) at FSB

Installation (for Mustang but similar to Broncos)
Source: by GTRaptor at allfordmustangs.com

Installation Instructions, Faze, General
Source: by tradervar.com

Installation pics, Oil Pressure, Water Temp & Transmission Temp., Auto Meter Night Vision in a 95
Source: by Ian L (stangmata, stangmata50l, Bronco) at SuperMotors.net

Installation, Oil Pressure, Water Temp & Transmission Temp., Auto Meter Night Vision in a 95
Source: by Ian L (stangmata, stangmata50l, Bronco) at bucknakedoffroad.com

Installation, Oil Pressure, Water Temp & Transmission Temp., Auto Meter Night Vision in a 95
Source: by Ian L (stangmata, stangmata50l, Bronco) at FSB

Installation, Sunpro,w/T for stock gauge in an 86
Source: by Sixlitre (Malcolm H, Eddie Bauer) at FSB

Installation, Sunpro,w/T for stock gauge in an 86
Source: by Sixlitre (Malcolm H, Eddie Bauer) at SuperMotors.net

Installation, Volt, Oil Pressure & Water Temp., Equus in an 86
Source: by Xris at SuperMotors.net

Installation, Volt, Oil Pressure & Water Temp., Equus in an 86
Source: by Xris at FSB

Instrument Voltage Regulator (IVR) in 78-86; "...The IVR can fail two different ways. it will quit working altogether, thus none of the gauges will work. Or two, it will stick, and the gauges will peg to the extreme right, then it will unstick and fall back to normal. The IVR is a pulse type. The voltage is regulated by how fast the pulses are. When it sticks, it doesn't pulse, etc... Try tapping on it. Make sure the cluster ground is in good shape. If the IVR isn't grounded or has an intermittant ground, it wont pulse like it should either. Rebuild it, see http://www.turbocoupe.org/techinfo/ivr/IVR.htmold or,Suggest getting one from a Yard; Since there are about 12 different types, make sure to take the old one with you; Fits: 1971/86 F100/350; 1971/91 Econoline; 1978/86 Bronco; 1977/79 LTD II/Ranchero/Cougar/Thunderbird without Tachometer; 1972/76 Thunderbird/Continental Mark IV; 1971/72 LTD/Mercury Marquis for MOTORCRAFT Part # GR513 (D1AF10804AA, D1AZ10804A)..."
Source: by miesk5 at FSB

Instrument Voltage Regulator (IVR) Location pic in 78-86; "...The cluster "voltage regulator" is going bad, and staying on too long, sending too much current through the gauges & sensors. It has finally locked on, and is burning out your sensors every time you turn your key on. :( Remove the instrument cluster and then pop the VR off the film circuit - it's a metal box with 2 brass snaps. They're available at most parts stores for a few bucks. The hardest part will be getting the headlight & wiper knobs off, so post again if you need instructions on that.In this photo, counting from the RIGHT, it's between the 2nd & 3rd black bulb holders along the top of the cluster. You can see the hex screw holding the mounting tab, and just below that, you can see the 2 brass snap terminals..."
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

Instrument Voltage Regulator (IVR) Pin-Out pic in 78-86; "...Back in the early 60's when Ford originally decided to go to a 5 volt system for the instruments the electrical engineers were faced with the problem of providing the guages with 5 volts. To make a true voltage regulator with 60's era parts would have been extremely expensive and the final product would have been about the size of a bread box. No good for their purposes. But since the guages are a hot wire design that doesn't respond very quickly to changes, the engineers were able to fool the guages into thinking that they had 5 volts by pulsing 12 volts to the guages. With the technology that is now avalible the IVR can be replaced with solid state components that supply a true 5 volts to the guages and put a stop to the wild dance of the guages..." READ MORE
Source: by James J at turbocoupe.org

Instrument Voltage Regulator (IVR) Repair in 78-86; "...Back in the early 60's when Ford originally decided to go to a 5 volt system for the instruments the electrical engineers were faced with the problem of providing the guages with 5 volts. To make a true voltage regulator with 60's era parts would have been extremely expensive and the final product would have been about the size of a bread box. No good for their purposes. But since the guages are a hot wire design that doesn't respond very quickly to changes, the engineers were able to fool the guages into thinking that they had 5 volts by pulsing 12 volts to the guages. With the technology that is now avalible the IVR can be replaced with solid state components that supply a true 5 volts to the guages and put a stop to the wild dance of the guages..." READ MORE
Source: by James J at turbocoupe.org

Location Diagram & Depiction in 87-91 (from Factory Manual and the Ford Electrical & Vacuum Troubleshooting Manual (EVTM)
Source: by Broncobill78 (Dave) at Ford Bronco Zone Forums

Location in Engine Bay Diagram in an 87-88 4.9L; #1
Source: by Ford via Chilton

Low or Erratic Readings Repair Tip in 87-88 Bronco & Ford Trucks w/ 4.9, 5.0, 5.8, & 7.3
Source: by Bob R at carquest.com

Oil Pressure Mod to Actual PSI "...short R in PCB..." in 87-88 F series trucks and Broncos
Source: by Mike & Debbie at rowand.net

Oil Pressure Mod to Actual PSI "...short R in PCB..." in a Ranger, but similar
Source: by rogueperformance.com

Oil Pressure Mod to Actual PSI "...short R in PCB..." info & NAPA Sender, etc.
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

Oil Pressure Mod to Actual PSI "...short R in PCB..."; "...So someone told me that my 92-96 F-series Oil Pressure gauge really isn't a gauge, it's more of and idiot indicator, this bothered me...:mad: So I decided to test the theory and of course they were right, wether it has 20#'s of pressure or 60#'s of pressure it stays in the exact same spot on the gauge. I tested the sending unit and it is a ON/OFF to ground switch. So I remembered that my old Fox body Mustang had a real working gauge so I found one of those big bulky sending units and the extension and installed it instead. Then it read really low on the gauge while idling.:headscratch: I looked at the EVTM and saw that there is a 20 Ohm resistor inline on the circuit. I pulled the cluster and sure enough there is a resistor smack dab on the cluster paper behind the oil psi gauge. I removed it and the gauge went dead. I soldered a jumper piece inline and POOF. See the pictures and video below..."
Source: by drvovru at FSB

Overview in 92-96; "The oil pressure system uses a switch and a fixed resistor; the resistor is attached to the engine wiring harness. A primary magnet, to which a shaft and pointer are attached, rotates to align this primary field, resulting in pointer position. The bobbin/coil assembly is pressed into a metal housing which has two holes for dial mounting. There are no adjustment calibrations or maintenance required for this gauge; Oil Pressure Sender - The oil pressure sender controls the magnetic oil pressure gauge's pointer position. The oil pressure sender ([b]switch[/b]) closes under normal engine operating conditions. The oil pressure sender opens with the engine off and no oil pressure..." read more
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

Re-Wiring 460 EFI Swap in a 79; "...OK, as usual, you will need, of course, the engine and accessories (if you want to run a serpentine belt), the computer and wiring harness (preferably out of a late 80'sor early 90's with either a C6 or a Manual Trans, can be either E or F series), as well you will need a fuel system that will be adequate to handle 40+ psi of fuel pressure, and a fuel pump that will deliver that 40+ psi of pressure (recommend a factory pump setup, or an aftermarket hi-pressure in-line fuel pump) (side note: I am taking that you have already taken out the old engine and have done the nessasary steps to install the 460 if the vehicle has not already had a Big Block in it already - 351m and 400 not included as big block). To start, you will need to do some re-wiring in the engine compartment, and also with the engine wiring harness. V+ Constant - Black/Orange - Yellow (EEC Power Relay/Fuel Pump relay). Switched - Red/Lt.Green - White - Grey/Yellow - Brown/White (HEGO, Coil, EEC Power); Fuel Pump V+ - Pink/Black (or it can be Orange/Lt.Blue); V- - Black/Lt.Green - Black; Starter V+ - Red/Blue (it also connects to the distributor); Coolant Temp Sensor - Red/White, and Oil Pressure Sensor - White/Red; A/C Compressor - Black/Yellow (if you have no A/C, you can hook it up to a switch 12V, and use it as a bit of a high idle, I think that itwill take it up to 1100 - 1200 rpm; Speed Sensor - Dk.Green/White and Grey/Black (I don't use this, I only put this in here so you know about them), I have had no problems with the truck, not running the sensor, it has not kicked up some engine codes and or suffered any problems; Reverse Lights - Black/Pink and or Purple/Orange; Neutral Saftey Switch - Red/Blue; Check Engine Light - Brown, or Brown/Red;Well, that should be all the wiring color codes and attachments....now comes the actual swap..." READ MORE
Source: by Tom (origin, Mr.TroubleMaker) at nelson.macd.ca site via web.archive.org

Sender Connector Location Diagram, Engine Area in 92-93 4.9
Source: by Ford via chiltonlibrary.com

Sender Connector Location in Engine Bay Diagram in a 90 4.9L Page 1
Source: by Seattle FSB (SeattleFSB) at SuperMotors.net

Sender Connector Location in Engine Bay Diagram in a 90 5.0 & 5.8 Page 2
Source: by Seattle FSB (SeattleFSB) at SuperMotors.net

Sender Failure; "Corrosion or faulty electrical connections; If the oil pressure gauge is pegged low after the engine is running, or is pegged high after the engine is running, or if there is intermittent illumination of an oil pressure indicator light, the sender could be faulty. Related Components to Check; All appropriate electrical connections to and from the sender The oil pressure gauge or indicator light; Appropriate fuses (see Shop or Owner�s Manual for fuse layout)..." miesk5 Note; enter applicable info for year, etc.
Source: by MOTORCRAFT�

Sender Location in a 4.9 Parts Break-Out Diagram; Internal & External; (#35)
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

Sender Location in a 460; "...is at the back of the engine between the intake and the bell housing,it has a single wire going to it.These oil senders go bad quite often.To test the guage,hook a jumper wire to the sender wire and ground and turn the key to the run position-the guage should read approx 1/2 way.If the guage doesn't read 1/2 way,then the wiring or guage is faulty.If it reads 1/2 way and the engine doesn't rattle or knock,then the sender is probably at fault..."
Source: by bronco1 at FSB

Sender Location in a 460; "...located on the top of the block at the rear of the engine, back edge of the lower intake..."
Source: by Dustin S (Dustball, Mellow Yellow, Mr. Laser Boy) at FSB

Sender Location pic in a 90 5.0
Source: by Shawn C (El Trucke Trucke) at SuperMotors.net

Sender Location pic in a 90 5.8
Source: by Vincent C at autorepair.about.com

Sender Location pic in a 90 5.8
Source: by SeattleFSB (Seattle FSB) at SuperMotors.net

SUNPRO Installation Instructions, General
Source: by tradervar.com

Symbols in Wiring Diagrams
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net

T's for Oil & Transmission Gauge Sensors pics in an 88
Source: by csn.rebel (CSNREBEL) at SuperMotors.net

Test & Installation Tips in a 90; "...My oil pressure gauge was reading on the "N" of the NORMAL range. After doing some research it seemed like it could be the oil pressure switch, also known as a sensor or sending unit. Disconnect the wire from the switch, ground it to the truck and turn the key on. If your gauge quickly moves to the left, the problem is most likely the switch. The switch on my 5.8 is located near the oil filter. It is in a difficult spot to work on so I advise that you go to NAPA and get an Oil Pressure Switch socket to do the job. The cost is about $7-$8, this will save you time and will help you reinstall the new switch. Wrap some teflon tape around the threads and install. Make sure that it is in tight, I don't know about torque specs, I just put mine in quite snug. Hook the wire back on and start your engine. For me it was the cure. My oil pressure now reads over near the "M" on NORMAL..." miesk5 Note; The stock gauge & Sender will drop off after pressure reaches a certain level. You might actually have 5 psi, but the gauge will read 0 PSI & "...Technically all you need is 10 psi of oil pressure per 1,000 rpms . I still would not feel comfortable with less then 20 psi at idle. If it is lower then that, you can also get a thicker oil." by 420nitro
Source: by Canoeboy146 at FSB

Test & Overview in a 96 from 1996 F-150, F-250, F-350, Bronco, F-Super Duty Motorhome Chassis Workshop Manual: The oil pressure gauge is a magnetic movement design consisting of a bobbin/coil assembly, a return to zero magnet and a primary magnet. The shaft and pointer are connected to the primary magnet. The bobbin/coil assembly is pressed into a metal housing which has two holes for dial mounting. The gauge operates through a pressure activated switch. When the engine is started engine oil pressure closes the switch, providing a ground circuit for the gauge coil. Current flow through the gauge coil to ground causes the primary magnet and pointer to rotate, providing an oil pressure reading on the dial face. The oil pressure gauge does not require adjustment, calibration or maintenance. Also, never remove the pointer indicator from its shaft. The oil pressure switch controls the magnetic oil pressure gauge's pointer position. The oil pressure switch closes under normal engine operating conditions (oil pressure above 42 kPa [6 lb/sq in]). The oil pressure switch opens with the engine (6007) off and no oil pressure. Check gauge operation as follows: With the key in RUN and the engine off, disconnect wiring connector at the switch. The gauge should indicate on the LOW graduation or below. Connect the wiring connector to the engine block ground. The gauge should indicate just slightly above mid-scale. If the oil pressure gauge tests within calibration, replace oil pressure switch. If the gauge still tests out of calibration, replace oil pressure gauge.
Source: by Ford via miesk5 at FSB

Test in a 460; "...is at the back of the engine between the intake and the bell housing,it has a single wire going to it.These oil senders go bad quite often.To test the guage,hook a jumper wire to the sender wire and ground and turn the key to the run position-the guage should read approx 1/2 way.If the guage doesn't read 1/2 way,then the wiring or guage is faulty.If it reads 1/2 way and the engine doesn't rattle or knock,then the sender is probably at fault..."
Source: by bronco1 at FSB

Testing in a 96; from 1996 F-150, F-250, F-350, Bronco, F-Super Duty Motorhome Chassis Workshop Manual
Source: by Ford via thedieselstop.com

Wiring Diagram in a 78 Bronco & 76-78 F Series
Source: by Blue79 at photobucket.com

Wiring Diagram in a 78, Haynes
Source: by Mike S (Broncster, BRONKSTER) at SuperMotors.net

Wiring Diagram in an 81 F 150
Source: by Chilton via miesk5 at FSB

Wiring Diagram in an 84 (diagram #4)
Source: by toddcomputer.com

Wiring Diagram in an 86
Source: by Xris at SuperMotors.net

Wiring Diagram in an 86 & Ford truck
Source: by Agnem (The Moosestang) at webshots.com