Instrument Panel Gauges

[teachmz]

I have a 68 ford truck and my gauges started pegging when the headlights were turned on, as well as instrument cluster, which started strobing. I replaced the IVR, thinking this was the problem, but the problem continued. I took the truck out when the panel seemed to be working, but when I turned the headlights on, the gauges began moving erratically again. In my frustration, I pounded on the dash twice and the problem seemed to have fixed itself, if only temporarily. The gauges are back to doing the same erratic behavior and I have adjusted the IVR a few times counter-clockwise, hoping for the best. If you have any suggestions on this, please post any information you might have. Thanks!

[69fordfan]

sorry i dont have a good reply for your problem, but i am very interested in the solution to your problem. have you solved it yet? if so please tell me what you found. if not i will keep my eyes and ears open for you.
69fordfan

[basketcase0302]

When you say "IVR", I'm assuming you mean:
Instrument
Panel
Voltage
Regulator

Here's the tutorial on how to properly adjust the IPVR:
http://www.fordification.com/tech/fuel- ... -units.htm
Your 68 would not have a printed circuit board, so I'd also look at the panel wiring for suspected loose wires or loose terminal connections on the panel. While running the engine check the wiring on the panel-that should tell you if/where there is a wiring issue.

[PhantomoftheBumpside]

Just a question...

Did you recently 'upgrade' your headlights to LED or HID?

[teachmz]

I have checked the wiring. All seems good. Replaced the instrument panel voltage regulator and the cigarette lighter. Still having the same problem. Will replace the resister wire next, then try the alternator. Thanks for the link to the wiring. Will check that out as well.

[sargentrs]

If pounding on the dash temporarily "fixed" them I'd be thinking bad/loose ground. Plus, if they ALL act that way then grounding is the only thing I can think of that's common to all of them. But then again, I know very little about electrical.

[69fordfan]

well......????hows it going? been watching to see how your progress is coming. no news- good news i hope! let us know.

[teachmz]

Okay, so I have been working tirelessly on my truck along with the instrument cluster in order to figure out why they are pegging out. My best guess after talking with many different people and mechanics; the problem seemed to lay with grounding the alternator, while making sure the water temp sending unit has no Teflon tape or sealant. The water sending unit must have metal to metal contact, otherwise, the surge will go through oil pressure sending unit, which in turn, makes the other gauges spike. No Teflon tape or sealant should be on oil pressure sending unit as well. You may have to dial back or dial forward your instrument panel voltage regulator in order to get the correct reading. Check these three things, and if your wires are still good, then you should have no problem as long as it is metal to metal. I hope this information is helpful to those in the same dilemma. Good luck!

[70_F100]

Okay, so I have been working tirelessly on my truck along with the instrument cluster in order to figure out why they are pegging out. My best guess after talking with many different people and mechanics; the problem seemed to lay with grounding the alternator, while making sure the water temp sending unit has no Teflon tape or sealant. The water sending unit must have metal to metal contact, otherwise, the surge will go through oil pressure sending unit, which in turn, makes the other gauges spike. No Teflon tape or sealant should be on oil pressure sending unit as well. You may have to dial back or dial forward your instrument panel voltage regulator in order to get the correct reading. Check these three things, and if your wires are still good, then you should have no problem as long as it is metal to metal. I hope this information is helpful to those in the same dilemma. Good luck!

A good sealant such as Loctite PST (Pipe Sealant with Teflon) http://www.henkelna.com/cps/rde/xchg/he ... 000001FDU3 should be used on both the temp and oil pressure sending units. Otherwise, you're asking for a leak.

There will be enough threads making good contact to provide the needed ground.

Teflon tape is not a good choice, by any means.

[teachmz]

The sending units are made of brass, therefore, the holes are tapered and so far no leaks. I will take you up on your suggestion if there is any. Thanks. So far the gauges are working properly and are not pegging out and fluctuating.

[knightfire83]

My guess:

Corroded / rusted / broken ground to the cluster.

Headlight switch off: The cluster is back feeding it's ground thru the dash lights which are connected thru the parking / taillights lights at the headlight switch.

Headlight switch on: The ground is eliminated that the cluster was using, resulting in the weird situation you are having.

I would fix the factory ground or make a wire with two ring terminals. One attached to the cluster and the other to a new good ground somewhere under the dash area.


Alternator: has the best ground being attached directly to the engine & so is the neg. battery cable.
Sending units: Run independent of each other and connect directly to the gauges. Not likely the culprit in this situation.
IPVR: Doesn't have any connection to the dash lights, which are also described as a problem, except for a common ground.