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Discussion Starter #1
I'm working on an 81 Elcamino. The only gauge that appears to work properly is the fuel gauge. The voltmeter stays on "0" even though I know the charging system is working, the temp gauge doesn't register and the oil pressure gauge barely moves at all.

Any ideas what could cause this?



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The only advise I have is head down to your local library. I don't know about where you live but here the referance section has a passel of old automotive repair manuals. You should be able to locate a wiring diagram on your 81 Elky.
 

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Have you had the cluster out? The cluster plug has a black wire, it's the only black wire, it should be grounded, if it's not the gauges will not work correctly. The fuel gauge may be indicating but it's likely not correct. Check the ground wire and the cluster plug connection make sure it's correctly in place.
 

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Discussion Starter #4
I'm in the process of removing the cluster. I'll post back when I get it out. Thanks.
 

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Discussion Starter #5
Pulled the instrument cluster. The only connector on it is the main one that connects the printed circuit sheet. I don't see another ground wire anywhere.

I tested the continuity from each of the connectors where the gauge cluster plugs in to a point on the connector end of the printed circuit sheet. Each of the connectors tests OK back to some point on the sheet connector. Any ideas?
 

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One of the wires of the connector is black. That wire connects to ground at the other end. You should also have a pink/black wire that is hot when the ignition is on. That pink/black wire supplies voltage to the gauges. If you have power on the pink/black and the black wire is grounded then the volt gauge should work.The other three gauges also get power from the pink/black and ground via the black wire, in addition to the varying resistance to ground of the respective sender.
 

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Is the gauge cluster factory installed?

If not, you'll get either one of two things.

CRAZY readings on the gauges (like temp off the high end when the car's bone cold)

or none at all.

You have to change the wiring pins and stuff around to match the year of car that you got the cluster out of, and make sure you have the proper sensors installed in the motor to send the correct signals to the gauges.

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Discussion Starter #8
The car has factory gauges. One question though, there are two coolant sensors on this car, one up by the water outlet with the thermostat inside, and one on the left side near the front mounted in the block. Which of these provides signal for the temp gauge?
 

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The temp sender will have a single dark green wire, the oil pressure has a tan wire and the volt gauge is connected across a pink/black (you have three pink/black wires if you have power on one you should have it on all three)and the black ground wire. I assume you have checked and you have power and ground.
 

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Discussion Starter #10
Elree,

Thanks so much for your help. I've kind of got two projects going on this car at the same time. I'm rehabbing the steering column and I have the ignition switch out of the car, so some of the stuff I can't check until I get that back together.

I'll post later when I get the chance to work on this part again.
 

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Discussion Starter #11
OK, got my steering wheel back in shape so I can get to work on my electrical/gauge problems again.

I still have the whole instrument panel out. I checked the ground and it's good. I have 12 volts at the connector for the clock at all times as I should. There are two pink/black wires on the connector and one which is solid pink. The two pink/black wires have 12 volts standing on them when the ignition switch is turned on, but the pink one does not. Is is supposed to?

I found that the temp sensor had been removed and a mechanical one installed in its place which was also inoperative. I have a new temp sensor on order which should allow me to reconnect the green temp sensor wire (single). That explains the lack of indication on my temp gauge.

The oil pressure sender looks new, but now I'm wondering if is the right one or not. How do you tell if the sender is one that was designed to work with gauges or idiot lights? I have a sneaking suspicion that this sending unit is made for idiot lights instead of gauges. Is there a way to test the sender to see if this is the case. I would to replace the sending unit without knowing. So, this might explain the poor indication on the oil pressure gauge.

The voltmeter puzzles me though. It is constantly reading "0" even though I know the charging system is good. Is there some way to test the voltmeter out of the cluster? That would seem to be a relatively easy thing to do if you knew what you were doing, which I don't.

I've got questions, you got answers?




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The pink goes to the fuel gauge sending unit. The oil pressure unit for gauges should be about 1 ½” diameter and about 2” tall can. The oil light switch will be about 1” dia. that tapers to the 1/8” pipe thread and about 1 ½” tall. The volt gauge can be removed and tested. Just connect one terminal to the bat + the other to -. if it doesn’t work reverse the leads. If it doesn’t work then it’s a bad gauge. If it is bad it shouldn’t be too hard to find in a U-pull-it wrecking yard.

The connector should have the wires as follows. Starting with the black - ground, dkblue – right signal, empty slot, lt/blue – left signal, gray – dash lights, pink – to fuel tank sender, dkgreen – water temp sender, tan – oil pressure sender, brown – gen light, next row brown/white – check engine light, pink black – inst power, ltgreen – high beam light, yellow – seat belt light, dkgreen/white – V6 engine oil press switch/elect choke, tan/white – cruse control light, pink/black – inst power #2, white – tach signal and orange – clock (I think)

There is only two pink/black not three. My mistake.
 

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Discussion Starter #13
Thanks so much for the detailed information. This will really help. I'll post back after checking things out.
 

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Discussion Starter #14
I've checked things out about as well as I can. Is there supposed to be something that holds the plastic circuit card onto the black electrical connector? On mine it just sits in there when you put the instrument panel in place. It doesn't seem very secure so I don't think I'm getting good contact. For example, I have 12-13 volts standing at the black electrical connector on the "clock" pin, but when I push the I-Panel back into place and check at the place where the clock actually connects, there is no voltage there. If I check the plastic circuit sheet I have continuity between the correct connector on the sheet and the clock terminal on the IP. I think I've just got a loose connection of some kind. I've only had this Elky a short time and this problem has existed since I got it.

Any ideas?
 

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The connector should have built in clips one on each end that hold it in place. Removing the connector should require squeezing it to get it released.
 

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Discussion Starter #16
The connector has clips that hold it into the dash panel. They are in place and holding the connector pretty well.

But the ends of the plastic circuit sheet just lay loosely in a cut out place in the instrument panel that fits over the connector in the dash panel. It just doesn't seem to fit tightly enough there. I thought perhaps there should be something that makes everything connect tightly.

Based on your excellent information on the pin outs, it seems everything on the bottom row of the connector seems to be making good connections (turn signals, gas gauge, warning indicators, etc.) and working properly. But almost nothing that connects via the top row of the connector works properly (voltmeter, temp gauge, clock, etc.). I'm pretty convinced that the circuit sheet is good as I can check the continuity through it and it checks out fine. But when you put it in place, there's no voltage being supplied to the appropriate gauge connectors, etc. when the ignition key is turned on.
 

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Discussion Starter #17
Also, I did as you suggested Elree and took the voltmeter gauge out of the cluster and connected it via some jumpers directly across the battery and every is AOK with the voltmeter, so I'm back to my original problem, there is no voltage at the voltmeter connectors.

I have a bad feeling that there is a part missing from this instrument panel or something.
 

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Discussion Starter #18
Well, I think I finally got this one figured out. After investigating a little more closely, the place where the black connector plugs into the dash panel appeared to me to be sitting back further on one side than the other. I guess due to heat and age the plastic has sort of warped. I made a shim out of an old serpentine belt I had hanging around and wedged it between the steel frame around the dash and the dash panel. Now I have voltage where I'm supposed to and my gauges work again (those that have good sending units)!!

Thanks for all your help.
 
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