the tach works and that's it. Today I tried testing the sending units for the fuel and coolant. I had my dad eye the gauges as I touched the fuel green to a ground...nothing. So I went up front and tested the coolant.. nothing. But then something strange happened I touched the coolant sender to a ground and the fuel gauge went to the top, and stayed there. When I turn the key off the needle goes back down. Key on, goes back to the top. I'm guessing the circuit "board" In the cluster is crap?
Hard to see in pic but on the bottom left some of the plastic has even peeled up exposing some of the copper wire. I tried cleaning all I could but nothing changed. Also I'm guessing I prob need a new speedo transducer but maybe with a new instrument cluster that would fix that too? I'll try adding a ground and see if that helps. Drove quite a ways yesterday hoping to score a junkyard instrument cluster... was already gone. Dang! I mainly just want to get the coolant gauge working so it doesn't overheat while I'm fixing other crap...like the small backfire upfront and it's overall stumbling tone and running.

 

When you experience multiple issues with the instrument cluster, the first suspect would be a bad ground.

You might try running a new ground test wire and see if that makes a difference

 

Agreed that it is likely a ground problem

That cluster has seen a lot of dampness. Remove all those tiny acrews and nuts one at a time and clean...gently.... all the contact points on the p/circuit. Then run a new ground from that horizontal metal bar to a known-good ground point under the dash

Cheer
DD

 

That was the before pic. I got all the rust off the metal bar and tried to hit almost everything with electronic cleaner. I unscrewed all the screws and sprayed under them with cleaner. Maybe I should've taken them out one by one and sanded and cleaned them... my plan is to run a ground from the metal bar to a ground. Can this be done with a gator clip on it or should a hole be drilled and attached? Always looking for an easy way

 

It is pointless to cut corners. A proper earth connection is vital. Also, you must clean the connections, etc one by one and sand them lightly. A bit of spray will not do it on its own as the current that is passing through the gauges is minute. The Great Palm id very good on how to R&R each individual gauge.

 

True.. I'll take it back out and sand the connections a bit and take more time. I noticed the rusty bar and sanded it back down. Funny there's that much moisture and this car has no rust.

 

Took the instrument cluster back out today... when I plugged it in, some of the contact copper had folded over and a couple tracks where the plastic had lifted and crossed each other even... so I'm going to clean it all up better and add the ground and try to get the plastic to stay down and the copper on the tracks. Fingers crossed

 

Alright... today took off all the screws and sanded all the contacts and hit it with cleaner. Taped down some of the copper trails and soldered one of them that had broken at the bulb holder. And finally, put a ground from the metal rail to a ground...and voila, it's working! Well everything except the fuel gauge seems to have a mind of its own and the car won't stay running long enough to get a coolant reading(but that's for a later date). Woooo

https://streamable.com/ot3ts

 

Told ya, SIMPLE cars, made complicated by humans.

Well done.

Fuel gauge is possibly the sender all corroded up, just like the instrument cluster.

Save a champagne cork or 2 from the wedding, the sender float may be AWOL, and those corks work well.

 

haha