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86 Gauges max out

5756 Views 24 Replies 13 Participants Last post by  The Yak
for the last year or so, every couple hundred miles, randomly all my gauges would go from normal and slowly creep to max (pegged right) over a couple seconds, stay there about 20 seconds, then slowly drop to normal again.....never bothered me before today when it creeped up and stayed there......

...any ideas?
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sorry, NOT speedo and tach....the voltmeter is broken, so just gas, pressure, and temp..... 1986 Eddie Bauer 302 EFI
haunted
It the gauges did it in sync, probably something in the cluster.
guages that max

I had this issues on mustangs all 3 of mine. and followed the mustangs groups and it seems there is a bad ground on the cluster pack. I made a jumper to the guage cluster to the metal dash and never saw the issue again. i saw it 3-6 times a year.
mike
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.
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Hey,

Before you go nuts pulling the cluster apart (PITA Job), check your negative battery cable for excessive voltage drop. I've fixed many Ford vehicle gauge Voodoo problems by correcting cable connections. Many times when you disconnect the cable you'll see Chiapets growing on the surfaces. Clean them up good with a wire brush, sandpaper or something similar, coat all the surfaces with silicone die-electric grease (available at the local parts store) to prevent further corrosion, and away you go. :thumbup Your starter will last longer too, as it doesn't have to work as hard because of reduced available voltage. :toothless

If you understand basic electrical principles (voltage drop) which most folks don't even when they think they do :shrug , this will all make perfect sense to you.

Sorry, but I don't have the time or the space to explain it all here, but when I used to teach for the auto manufacturers, Basic Electrical was one of my favorites, cause you could really help people, and blow away all the dumb myths out there. It's funny how so many folks don't understand what they can't see (electron flow), but in reality, once you understand it, a basic digital voltmeter (DVOM) can tell you everything you need to know. It's not till you start dealing with electronic digital circuitry that you need to go beyond the DVOM to O-Scopes, but that's a whole different subject. Anyway, sorry I started rambling, but hope this helps. :rockon
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I am having same issues except with all my gauges. Sence there was no final resolution to this issue I am asking if cluster "voltage regulator" would cause the same issues on an 86 XLT bronco 302 EFI. Just started happening. Also noticed that when I pull the knob for head lights the blinkers on the dash come on and the "high beams" light comes on (dash). Yet the head lights won't. If I tap the high beam switch floor a few times the lights come on. I am just curious if the cluster could be causing this or if there is major issues somewhere else. Also just thought of something. I read there is a gauge cluster wire on the engine somewhere. Can anyone post a pic of it's location that way I could see if it is grounding as I would think that could cause the gauges to peg. Thanks all.
Your problem sounds like a bad ground.
I am having same issues except with all my gauges. Sence there was no final resolution to this issue I am asking if cluster "voltage regulator" would cause the same issues on an 86 XLT bronco 302 EFI. Just started happening. Also noticed that when I pull the knob for head lights the blinkers on the dash come on and the "high beams" light comes on (dash). Yet the head lights won't. If I tap the high beam switch floor a few times the lights come on. I am just curious if the cluster could be causing this or if there is major issues somewhere else. Also just thought of something. I read there is a gauge cluster wire on the engine somewhere. Can anyone post a pic of it's location that way I could see if it is grounding as I would think that could cause the gauges to peg. Thanks all.
That's because you ain't got the 3G 130 amp Taurus alternator on there yet.

You, me and Gus are all 86ers and believe me it goes away forever with a 3G !

Sixlitre
That on my 2 do list :rockon espically sence I have a set of roll lights on top and running extra lights on front and soon to have a winch. But wait let me stop ya right there Sixlitre, those itmes listed are not connected to battery right now. I also plan to do the dual battery red top and yellow tops. But can't go further till I get this thing kicked. Hell I can't even go at night as dash lights are not working or so dim that I can't see them. :doh0715:
That on my 2 do list :rockon espically sence I have a set of roll lights on top and running extra lights on front and soon to have a winch. But wait let me stop ya right there Sixlitre, those itmes listed are not connected to battery right now. I also plan to do the dual battery red top and yellow tops. But can't go further till I get this thing kicked. Hell I can't even go at night as dash lights are not working or so dim that I can't see them. :doh0715:
By all means fix your voltage drain, if you have one, but the red tops are LAST priority, after a used $30.00 Taurus alternator and this $12.00 parts allowing us 86'ers to do the 3G thing.

http://www.paperformance.com/scripts/prodView.asp?idproduct=73

You'll be just fine with one plain battery, once you get the 3G on there.

Sixlitre
Well I think I have narrowed it down to 3 possible things.

1. Ground for Roll lights.
2. Head light switch.
3. Radio.

The Previous owner added the lights and is grounding them right under the head light switch. He also added a after market radio but did his own rigging as it turns on without keys etc..I was driving last night and rolled the window down and turned the radio on and then realized the dash started working.
did you try what steve83 suggested?
Not yet, I need to get the rigged wiring fixed. If that don't solve it then Steves will likely fix it. Will let ya'll know what resolves it.
Well I think I have narrowed it down to 3 possible things.

1. Ground for Roll lights.
2. Head light switch.
3. Radio.

The Previous owner added the lights and is grounding them right under the head light switch. He also added a after market radio but did his own rigging as it turns on without keys etc..I was driving last night and rolled the window down and turned the radio on and then realized the dash started working.
Why is it every previous owner thinks he'd the lord's gift at installing electrical components (when they never are:banghead).

Good luck and try Steve's suggestions

Sixlitre
I agree with Bronco4Life
Sounds like you have a bad ground, (or a couple of them)

Here is a list of grounds for a '92 - '96 bronc

I took a look in my Haynes manual.
They list 10 separate grounds... A-J.

A. Starter mounting bolt
B. Right front of Engine compartment near the battery
C. Lower left front of engine
D. Right front of engine compartment on upper radiator support.
E. Left front of engine compartment Upper radiator support
F. Bottom of cowl panel
G. Rear of left fender apron
H. Behind bottom of right cowl panel
I. Left rear corner of cargo area near rear lamp assembly
J. Under center rear of vehicle on rear cross member.
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Being that I have a 86 would these grounds be on mine?
Being that I have a 86...
FILL IN YOUR PROFILE. :deal




....and upload an avatar. :popc1:
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