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Ammeter Issues

LAP66

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Any insight you can provide would be appreciated. Pulled the cluster on a 66 charger. Got all the gauges el working including the ammeter. Ammeter el works outside cluster. Does not work when mounted in cluster. It seems that the spacing washers on the ammeter threaded posts between the post nuts and the inside back of the cluster are preventing proper grounding contact as the spacers are slightly too thick preventing positive contact between ammeter rear housing and triangular grounding surface on the inner cluster housing. Is this correct or were the spacers placed by someone else incorrectly prior to myself. This was not the first time the cluster was pulled. When I remove these spacers the el on the ammeter works great as it is grounded properly. Thanks as this is driving me nuts!
 
I can't comment on the problem, it's been too long since I've had my dash apart.
But just the clarify for anyone else reading: the problem is the electro-illuminescent lighting, not the ammeter gauge itself.
 
From your description, you not getting a good ground between the aluminum casting bucket that all the gauges mount into and the ammeters small metal bucket housing. It's only the physical pressure applied by the ammeter stud screws that create the ground connection between these 2 pieces. It's important that the studs of the ammeter have the proper fiber shoulder washers and flat washers. There can be NO electrical contunuity between these studs and anything grounded. The heads of the studs must be making proper contact with the brass "shunt" bar inside the ammeter and be sufficently tight to assure contact as all basically everything electrical, short of the starter motor, passes through these terminals. You don't want any loose electrical connections on these studs, or any wires associated with these studs ! You may be able to attach or solder a wire between the meters small outer bucket and something grounded to solve your problem.
 
I don't like the fiber washers. I use grommets that fit tight. You get some long term vibration dampening and better insulation.
 
From your description, you not getting a good ground between the aluminum casting bucket that all the gauges mount into and the ammeters small metal bucket housing. It's only the physical pressure applied by the ammeter stud screws that create the ground connection between these 2 pieces. It's important that the studs of the ammeter have the proper fiber shoulder washers and flat washers. There can be NO electrical contunuity between these studs and anything grounded. The heads of the studs must be making proper contact with the brass "shunt" bar inside the ammeter and be sufficently tight to assure contact as all basically everything electrical, short of the starter motor, passes through these terminals. You don't want any loose electrical connections on these studs, or any wires associated with these studs ! You may be able to attach or solder a wire between the meters small outer bucket and something grounded to solve your problem.[/QUOT

Thank you for the reply. Nothing loose on the ammeter bucket. Nothing shorting out. When installed if I ground the ammeter bucket to the housing with a small wire the el lights up. The fiber flat washers seem a bit too thick to allow proper pressure when tightening the nuts to obtain a good ground. Bizarre and frustrating as nothing seems to be bent or warped. Cleaned both mating surfaces with steel wool and still no love! Thanks again. I’ll keep at it!
 
If the insulating washers are a tiny bit too thick you may want to get like 2 of the serrated external tooth lock washers, perhaps 8-32 or 10-32 size, not on the studs, but at the outer edges of the ammeter housing. Sandwich them between the gauge housing and alum. casting. When you tighten the studs, that extra thickness from the washers and teeth digging in should provide a suufficent ground.
 
So, what happened with this ?? You get it working properly ?
 
The ammeter from the factory has two very thin fiber washers installed on the posts and then the ammeter is installed in the gauge housing. Held on the back with two thick fiber washers with a lip to center the gauge in the housing. Then nuts hold the gauge in place. I rebuild these first gen clusters as a hobby business and this problem drove me nuts as it was the same as yours, EL works fine outside of the cluster....once you hooked up the ammeter to the dash wiring it would short out the entire EL. Nothing lit up. If you only have an ammeter lighting issue, it’s a ground problem. If it kills the entire cluster EL, it’s a gauge issue with the needle not being seated properly in the bottom pivot. Took me way too long to figure that out as the ammeter will still work with the needle outside the bottom pivot. But it will created a short when connected to the dash harness. Feel free to PM me if you need more info.

Thanks,

Mark
 
So, what happened with this ?? You get it working properly ?
Thanks for the reply. Got it working by shaving the fiber washer a bit so the ammeter seated a bit deeper in the housing and made contact with the housing. Don’t know if the fiber washers get a bit thicker over time because of humidity? Odd, but works fine now.
 
The ammeter from the factory has two very thin fiber washers installed on the posts and then the ammeter is installed in the gauge housing. Held on the back with two thick fiber washers with a lip to center the gauge in the housing. Then nuts hold the gauge in place. I rebuild these first gen clusters as a hobby business and this problem drove me nuts as it was the same as yours, EL works fine outside of the cluster....once you hooked up the ammeter to the dash wiring it would short out the entire EL. Nothing lit up. If you only have an ammeter lighting issue, it’s a ground problem. If it kills the entire cluster EL, it’s a gauge issue with the needle not being seated properly in the bottom pivot. Took me way too long to figure that out as the ammeter will still work with the needle outside the bottom pivot. But it will created a short when connected to the dash harness. Feel free to PM me if you need more info.

Thanks,

Mark
Thank you for the reply. Not shorting the entire cluster, just the ammeter not grounded. I shaved the fiber washers a bit to make them thinner so the gauge would contact and ground on the housing. Works now, the el that is. The thermal gauges are cooked however. Beyond my skills. I may contact you about a rebuild! It would be nice to actually know how much gas is in the tank! Thanks again!
 
The ammeter from the factory has two very thin fiber washers installed on the posts and then the ammeter is installed in the gauge housing. Held on the back with two thick fiber washers with a lip to center the gauge in the housing. Then nuts hold the gauge in place. I rebuild these first gen clusters as a hobby business and this problem drove me nuts as it was the same as yours, EL works fine outside of the cluster....once you hooked up the ammeter to the dash wiring it would short out the entire EL. Nothing lit up. If you only have an ammeter lighting issue, it’s a ground problem. If it kills the entire cluster EL, it’s a gauge issue with the needle not being seated properly in the bottom pivot. Took me way too long to figure that out as the ammeter will still work with the needle outside the bottom pivot. But it will created a short when connected to the dash harness. Feel free to PM me if you need more info.

Thanks,

Mark
Hello, how much do oyu charge to re build a 66 cluster?
 
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