Electrical Advice Needed

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domdart

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I am having problems driving at night. Everything works perfectly until I turn on the headlights. Sometimes the dash lights work, sometimes they don't. When the dash lights come on the fuel and temp gauge stop working. When the dash lights go out, the gauges work. I installed cracked back's headlight harness. My headlights are much brighter but all the other problems remained. Tonite I added a ground to one of the nuts on the cluster. I started the car and turned the headlights on. The dash lights came on at first but then went out. The fuel and temp gauges didn't work at all. I noticed my radio was on. When I touched the dial to turn it off I noticed my dash lights flickered then came back on. When I let go the dash lights went off. When I touched the radio dial the dash came back on. I was turning my dash lights on and off just by touching the radio on/off dial. I guess I was grounding the system. Please help!
Any advice will be greatly appreciated. Thanks FABO.
 
or switching a ground
Try unplugging all the plugs on back of radio or pull the fuse if it just controls the radio, if problem is still present try unplugging different items, note if it's a 71-72 A body there is a voltage limiter that plugs into the back of the cluster . Mike
 
Try unplugging all the plugs on back of radio or pull the fuse if it just controls the radio, if problem is still present try unplugging different items, note if it's a 71-72 A body there is a voltage limiter that plugs into the back of the cluster . Mike
You can check for voltage drop, I'd start at battery and bulkhead connectors and then inside and to column , you can make a good load testing light with a 1157 bulb, ohm testing can get you snake bit it could be searching for a ground, lights start out bright and drop off as ground resistance increases, can make heat be careful, you better be able to think fast if that bad boy goes up in smoke ! Mike
 
There are multiple problems with these clusters, you should take the time to pull it out and go through it

In no order:

The PC board connector pins can get loose/ corroded from the PC board traces, you must solder them (or buy a Repop PC board)

The contact fingers for the IVR (gauge limiter) lose contact with the PC board you must solder jumpers across

The IVR itself should be replaced with a solid state one

The gauge studs/ nuts corrode/ get loose. Loosen/ tighten them a few times to scrub the contacts clean

While you are in there, take an erasor and buff clean the copper PC board where the dash lamp sockets go. Bend / clean the socket contacts and clean the sockets and replace the bulbs

Add a ground (I guess you did) to the cluster, but make sure it is actually a ground

This thread has been around a while it is tremendous

Printed circuit pins repair
 
Sounds to me like your cluster "ground" might not be grounding. Also take the dash dimmer control, and in the dark, rotate it vigourously left to right to scrub the wiper clean. You may find it has a/ some "bad spots" where it doesnt make connection. For testing, you can clip a test lamp to the INST fuse. This fuse will be on one end of the fuse box

This fuse comes FROM the dash dimmer control on the road to the dash lights. You can use it for a "monitor" to see if it still lights when you lose the dash lamps

You will only have power on that INST fuse when the tail lamps are on and working, and when the dash dimmer is rotated far enough left to give it some "juice"
 
There are multiple problems with these clusters, you should take the time to pull it out and go through it

In no order:

The PC board connector pins can get loose/ corroded from the PC board traces, you must solder them (or buy a Repop PC board)

The contact fingers for the IVR (gauge limiter) lose contact with the PC board you must solder jumpers across

The IVR itself should be replaced with a solid state one

The gauge studs/ nuts corrode/ get loose. Loosen/ tighten them a few times to scrub the contacts clean

While you are in there, take an erasor and buff clean the copper PC board where the dash lamp sockets go. Bend / clean the socket contacts and clean the sockets and replace the bulbs

Add a ground (I guess you did) to the cluster, but make sure it is actually a ground

This thread has been around a while it is tremendous

Printed circuit pins repair
..........
And put No Ox on terminations
 
I unplugged the radio connector. The dash lights, dimmer, and headlights all work fine. My gas and temp. gauges no longer work. The cluster ground I hooked up was hooked up to one of the gauge posts on the back of the cluster. This is probably why those gauges no longer work. Now what? New voltage limiter? What do I check so I can hook up the radio? Thanks FABO.
 
I removed my instrument cluster. The gauge side circuit bard looks damaged. I started a new thread with an image of the damage, asking if it can be repaired.
 
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