Hello All !

I've had the dash out to replace a fuel gauge that I suspected is bad, based on using an ohmmeter to measure the resistance increase on the circuit to conclude everything else from the tank to the dash plug is working like it should. While I had the dash out, I replaced the integrated voltage regulator as I replaced all of the other dash components a couple years back except the IVR. Now, my oil pressure, temperature and fuel readings are LOW. Normal / legacy readings for the oil pressure are H at startup and the middle once warm and idling; the temperature normally reads around the "E" when the engine is running at 200F (I have an analog gauge on the thermostat housing unit). SO... either the old IVR made everything read high, the new IVR is making everything read low - or it's something else completely.

I suppose as long as I use the gauges to notice readings "out of the normal", it may not matter what the "normal" is. BUT, the original reason I pulled all of this crap apart was a cranky fuel gauge (noted via another post / thread). The IVR powers the temp, fuel & pressure gauges; not my volt (yes, volt) gauge. I installed a new fuel gauge from Tom's Broncos and the photo shows it reading with a just-filled tank, so right now I'm an unhappy camper at the thought of digging through the garage trash can for the old IVR to see what happens if I reuse it with the new fuel gauge. Any other ideas / would you do something else?



Thanks,
- IH

 

Man I wish my dash lights were that bright.

 

I've never seen the oil pressure gauge to clear over the the H, so I'm going with the first one was making the gauges go higher than "normal"...

 

Did you adjust the voltage regulator?

 

Maybe the wrong IVR? Don't know if there are different ones. I don't think they are adjustable. Maybe a ground problem in the connector.

 

There are calibration procedures for the gauges described in the Ford Truck Shop Manual. They will determine if the instrument voltage regulator should be replaced. It should have a pulsating value averaging 5.0 volts. In the 1976 manual it appears in section 33.

I agree that you gauge illumination looks great.

 

Thanks guys and I have a FTSM to review. illumination comes from LEDs in the dash. I guess checking the IVR will tell me if my new fuel gauge is bad(?)...
- IH

 

You can also take ohm readings from the sender and see what they are when you know that the level in the tank has changed..
I wonder if anyone has ever tooken one of these IPVRs apart. I'm guessing that there's a set of points in there that you might be able to clean?

My '82 Mustang GT used to make a small metallic buzzing noise, and the Fuel, Oil, and Temp gauges would peg full high. With old Fords, if you see one gauge abnormality, it's time to check the rest of the gauges...

 

Adjusting the IVR is covered in the FSM.

 

Thanks Ozzie. I looked in the FTSM. There are procedures to test the IVR using a piece of test equipment, which I do not have. I see from GasHog's response that the IVR is adjustable, although both the old and new units look sealed(?). I will reconnect the dash, reconnect the battery, turn the ignition switch to on and take voltage readings from selected circuits on the back of the printed circuit board to ensure they are around 5vDC (without accidentally grounding anything and cooking the circuit board).

Re: the fuel gauge circuit, I vampire tapped another wire from the one feeding resistance from the fuel sending unit to the gauge and it's reading 17 ohms this morning (which is odd, because last fill up it read 10...)

UPDATE: Hung the dash unit upside down and away from metal, left of the steering wheel. Measured voltages to the gauges and they read between 4.6 - 4.9 oscillating fairly constantly. I assume this is what Ford promises with 5vDC? Will wait to hear from someone who's messed with this before I button everything back up and live with the gauges (for now); not sure if I need to adjust the IVR to read five full volts? Maybe I'll look at the aftermarket to see if there's something better to work with than this funky setup...

Thanks!
- IH

 

D1AZ-10804-A .. ICVR ~ Instrument Cluster Voltage Regulator (Motorcraft GR-513) / Obsolete

Affects the fuel, temperature and oil pressure gauges. Attaches to the printed circuit board.

1971/86 F100/350 // 1971/91 Econoline // 1978/86 Bronco // 1983/86 Ranger // 1984/86 Bronco II / Some 1971/79 FoMoCo Passenger Cars.

The factory installed ICVR has a hole in it that the end of a paper clip or ice pick could be inserted to reset it. The replacement ICVR's do not have this feature.

 

Thanks Bill. Do you suggest that I trash the replacement IVR, dig the original out of the garbage can and reset it, then test voltages?

 

The stock IVR is adjustable with needle nose pliers. The small screw rotates, the GR513 is available on Ebay NOS.

 

Thanks and sorry I haven't posted progress. I've been busy and my Highboy is sitting in the garage with the battery disconnected. I did fish out the legacy IVR and will pop it back in to take voltage measurements / see how the gauges respond when I get a free moment - then let you know how it turns out. I appreciate the added brains FTE provides - thank you
- IH

 

Update and two new questions. After concluding that the "new" IVR was just making all of the gauges read too low, I yanked the legacy part from the garbage can and have been adjusting the screw up and down to find a better effect on the gauge readings. This has tried my patience and I'm ready to pay for an aftermarket dash cluster - although the two I found perusing this website don't look so neat - any suggestions?

MORE IMPORTANTLY... my headlamp switch is now failing to release the **** rod- the button on top pushes down but something must be worn such that it's not releasing the rod as it should. The **** set screw is stripped, so I cannot remove the **** and cannot re-install the dash frame. I can replace the switch assembly easy enough and cut the rod & **** - BUT I'm hoping someone has experienced this before and will please provide a more elegant fix. I'm not often mad at my truck, but this entire experience has been a total pain in the @ss, especially since I rebuilt all of this a couple years ago and had everything working perfectly