gauge refurb?

[plugugly]

Was watching videos of how to refurb, clean etc gauge clusters last night.

1. One of the videos showed that using a 9v battery, one could test the gauges by touching the back of cluster, the little prongs that hold the gauge terminals. When I do that, only the oil pressure gauge moves. ANd, it does it when I test the voltmeter and water temp gauges too. Im guessing its not suposed to do that? Im gong to pull the gauges and test them individually, but does that mean the electronic mat thing on the back of the cluster is damage somehow?

2. The voltmeter only has 2 of the little prongs. Should there not be three? Perhaps there are only two posts on the voltmeter, I guess Ill answer that when I pull the gauges. If it requires 3, can those be sourced anywhere?

 

[plugugly]

so water, volt and oil all tested fine independently using the 9v batter.

I am missing one of the little clips for the volt meter. No idea where that went. Can they be sourced? If they are no longer available but from a junkyard, what years would have them as you all know the old trucks are harder to find, so does it stop at 87 or go into the 90's?

Still tring to figure out why when testing the back of the gauges when installed, only the oil press gauge moves.

 

[87gmcburb]

so water, volt and oil all tested fine independently using the 9v batter.

I am missing one of the little clips for the volt meter. No idea where that went. Can they be sourced? If they are no longer available but from a junkyard, what years would have them as you all know the old trucks are harder to find, so does it stop at 87 or go into the 90's?

Still tring to figure out why when testing the back of the gauges when installed, only the oil press gauge moves.

Not sure about testing with a 9 volt battery. The clips you mentioned are available from LMC truck. The older ones are a bit more stout and better if you can find some OEM. The circuit board ("electronic mat thing") is fairly simple. check the bare spots on the board where the clips touch and where the wire harness plugs into. Clean these up and make sure they make good contact. The same for the bulb holders since you have it out. I would bench test each gauge individually out of the cluster.

 

[Bennyt]

so water, volt and oil all tested fine independently using the 9v batter.

I am missing one of the little clips for the volt meter. No idea where that went. Can they be sourced? If they are no longer available but from a junkyard, what years would have them as you all know the old trucks are harder to find, so does it stop at 87 or go into the 90's?

Still tring to figure out why when testing the back of the gauges when installed, only the oil press gauge moves.

Post a picture of what you need. I believe I have 1-2 broken clusters I can pull from for you.

 

[plugugly]

I think I need one of these? At least I only have two and there is a space for three.

Ecklers Printed Circuit Retainer 73-87

1981-1987 Chevrolet Truck C/K 1981-1987 GMC Truck C/K 1981-1991 Suburban 1981-1991 Blazer 1981-1991 Jimmy

www.ecklers.com

Edit: After looking through that below video again, I see he only has 2 prongs at the voltmeter like I do. The issue is, wehn I bench test the gauges, the gauge terminal which needs to be powered to sweep the needle is the one that has no prong. So now I am really confused.

all my gauges bench test fine. Still not sure whay only the oil pressure gauge changes when testing the back of the gauges when they are installed in the panel.

As for the 9v testing thing, I got it from this video

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[plugugly]

so voltmeter is totally not working. When probing the two terminals on it voltmeter, I do not get any OHMS reading between them at all. So I am guessing the resistor is dead?

I checked the harness itself. All grounds have continuity, as do the temp and pressure leads, and they are attached to the individual sensors. I get 12ish volts with key on at the pink/black wires. I get 12ish volts to all the hot side of the gauges, so I know they are getting power.

Everything else seems correct unless the printed circuit is wrong or there is something I am missing.

the picture below is of the volt gauge above where it mounts in the panel. If I put nine volt power to the right terminal (with no corresponding cluster prong) and ground to the top terminal, the gauge will sweep all the way to the right. If I put power to the left terminal I get nothing. If I ohm between the left and right terminals, I get nothing. So I am guessing the power from the printed circuit applies to the left, it goes through the resistor to the right terminal and that causes the gauge to sweep to the correct location. Does that sound right?

Where can I get the resistor?