Instrument Cluster
Thread Starter
Instructor
Joined: Oct 2002
Posts: 213
Likes: 0
From: Choudrant LA
Instrument Cluster
Yet another post about the NOTORIOUS early C4 instrument cluster!!!!!! Mine is flickering and will shut out completely, then come back on and so on. Its completely feaking out!!!! I have seen some of the previous posts on this telling how to fix the wiring, but I was just wondering if anyone knew anywhere to see detailed pictures or instructions on removal and repair of the unit. I really don't feel like forking over several hundred to have it fixed!!!! Thanks again!!!!
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Instrument Cluster (eric_daniel)
You can get some help from http://www.batee.com Most likely your cluster is intermittent due to an unsoldered pin on the forward circuit board. There is a single row of pins on the front board that plugs into a socket on the rear board and the end pin closest to the center of the circuit board carries the lamp current. The age relaxed spring on the socket causes connection resistance and the lamp current makes so much heat that it usolders the pin on the front board. Resoldering the pin won't work, the socket needs to be replaced, or you can do as I did and solder a small insulated short piece of hookup wire from the pin to the socket and never have that problem again.
Thread Starter
Instructor
Joined: Oct 2002
Posts: 213
Likes: 0
From: Choudrant LA
Re: Instrument Cluster (jfb)
Jfb, I have seen several of your posts and you really seem to know about these. Mine is not just the lights flickering but the whole set is resetting. It is acting just as if you were to restart the car and all of the lights show then go off. Even the mileage resets. I appreciate the help!!!
By the way its an 85.
By the way its an 85.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Re: Instrument Cluster (eric_daniel)
I'd start by checking power & grounds, though with an intermittent, this may not find the fault. Power lines are: D5 from the LCD fuse, memory function - battery voltage key on & off; D16 & C16, ignition on from the cluster fuse, system voltage with key on and engine running. Be sure to check voltages with a DVM. Normal draw for memory is suppose to be 3.5 to 5.0 milliamps, but that's probably only useful if the battery is dying overnight or if when you go to start it the next day, everything is back to zero. Grounds are D1 & D3. With your DVM set to ohms and the black lead grounded, check by connecting the red lead to the ground wire at the cluster connector (disconnected). Should be zero. (Be sure to touch the leads together first and then ignore or subtract any resistance in the leads). An old recommendation is to solder the grounds together at the cluster with the theory being that if one was bad, the other was good. You can try this without hurting the cluster.
Pro
Joined: Sep 2003
Posts: 670
Likes: 1
From: charlotte nc
Re: Instrument Cluster (Shylor)
I had similar problems with my 86. I tried all the suggested fixes to no avail. I finally bit the bullet and sent ot off for repair. Turns out, I had a bad power supply. Best 200 bucks I ever spent. :cheers:
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