'85 digital dash question
Thread Starter
Instructor
Joined: Aug 2004
Posts: 155
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From: CA
'85 digital dash question
I guess is is my turn to have a digital dash problem ...but have not seen this specific one discussed (at least it didnt show up in my searches). Now that it gets dark earlier, it is very noticable.
When I am driving...the dash will randomly go dark. It does not seem to be related to bumps or turning or any mechanical change in the car...it just goes dark. Then after a few minutes it will just as randomly come back on. The high beam and turn indicators dont act up....it is like a switch gets turned off and then back on. I have a dash cluster repair book and a have read about ground problems etc...but they refer to the high beam indicators as a sign of the problem... but I dont see that. Also ...when I stop the car and restart the dash resets and works normally until the next time it goes dark. It happens a least once per hour of driving and mainly after the car reaches operating temp...never when it is cold. Any thoughts?
When I am driving...the dash will randomly go dark. It does not seem to be related to bumps or turning or any mechanical change in the car...it just goes dark. Then after a few minutes it will just as randomly come back on. The high beam and turn indicators dont act up....it is like a switch gets turned off and then back on. I have a dash cluster repair book and a have read about ground problems etc...but they refer to the high beam indicators as a sign of the problem... but I dont see that. Also ...when I stop the car and restart the dash resets and works normally until the next time it goes dark. It happens a least once per hour of driving and mainly after the car reaches operating temp...never when it is cold. Any thoughts?
Safety Car
Joined: Nov 2004
Posts: 4,991
Likes: 5
From: The Pines South Jersey
Originally Posted by LangstC4
I guess is is my turn to have a digital dash problem ...but have not seen this specific one discussed (at least it didnt show up in my searches). Now that it gets dark earlier, it is very noticable.
Also ...when I stop the car and restart the dash resets and works normally until the next time it goes dark. It happens a least once per hour of driving and mainly after the car reaches operating temp...never when it is cold. Any thoughts?
Also ...when I stop the car and restart the dash resets and works normally until the next time it goes dark. It happens a least once per hour of driving and mainly after the car reaches operating temp...never when it is cold. Any thoughts?
Stay tuned, I am going to attempt to do a vid clip tutorial of a cluster repair over the hoildays. I am confident I can fix it, as long as I dont need any parts, on my kitchen table. So long as my 4yr old doesn't try to solder I should be ok with the only thing remaining is to make a good ground back at the car.
At the same time I will be testing a "new" product for cleaning and preserving electrical contacts and reostats, I may even do the Blose if time permits.
Back to the cluster, I am expecting the 882's w sockets to arrive on the 23rd and expect to do the repair on the 27th.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Sorta sounds like the onboard power supply in your cluster might be on it's last legs...
If that's the case soldering won't really help much. But you could always try to take it apart and clean and fix the solder joints, it won't hurt.
If that's the case soldering won't really help much. But you could always try to take it apart and clean and fix the solder joints, it won't hurt.
Thread Starter
Instructor
Joined: Aug 2004
Posts: 155
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From: CA
I forgot to mention that the guages and readings are all still working during the dark spells...in the daylight I can still see them faintly in the cabin light...but no illumination. Kinda rough going at night though.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Originally Posted by LangstC4
I forgot to mention that the guages and readings are all still working during the dark spells...in the daylight I can still see them faintly in the cabin light...but no illumination. Kinda rough going at night though.
www.batee.com is an excellent resource by the way
Last edited by mikey whipreck; Dec 18, 2004 at 12:37 PM.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Originally Posted by jd_v3tt3
Any source for parts?
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Team Owner
Joined: Mar 2001
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From: Cincinnati, Oh USA
There are two circuit boards in your cluster and they plug together with a single row of connectors. The pin closest to the center of the circuit board carries the lamp current and the socket on the rear board has an age relaxed spring and now has connection resistance. The lamp current passing through this connection resistance makes so much heat that it has unsoldered the pin on the front board and it makes intermittent connection causing your 4 lamps to go on and off randomly. Resoldering the pin will not fix this problem and replacing the socket is difficult. I soldered a short piece of insulated #22 hookup wire from the pin to the socket and I will never have that problem again.
Racer
Joined: Sep 2004
Posts: 317
Likes: 1
From: 84 Blue A4 Garrison Ky
My 84 had somewhat of a similar problem, i resoldered all the connections and didn't really help. Soldered a extra ground wire onto top pcb and ran out to engine ground, the one on top in the front, and display is now very steady.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Haven't checked the "search" for a long time, but if you can find thread #885976, it has an excellent color picture of how and where to add an additional wire for ground in the circuit board. The rebuilders all seem to piggy back ground wires in their repairs. If you can't find it-just email me, don't know how to email it, but I can certainly fax it to you if you need it. Good luck.
Thread Starter
Instructor
Joined: Aug 2004
Posts: 155
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From: CA
Originally Posted by rick lambert
Haven't checked the "search" for a long time, but if you can find thread #885976, it has an excellent color picture of how and where to add an additional wire for ground in the circuit board. The rebuilders all seem to piggy back ground wires in their repairs. If you can't find it-just email me, don't know how to email it, but I can certainly fax it to you if you need it. Good luck.
The defective photo sensor idea seems promising (when I hold my finger over it...it dims out slowly to the same level, and the problem is probably temp related (as the car is warm when this happens)...but I cant find anything written on bypassing the sensor. The book I have speaks of grounding the ambient temp sensor near the firewall somewhere...but I have not found it yet (maybe not an '85 part).
The dash dimmed out twice yesterday coming and going from a sunny run to Capitola...ran great this morning in the 40 degree fog. As much As I hate the idea ...I think the dash is coming out over the holidays. Thanks for all of the help and suggestions.
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Originally Posted by LangstC4
I )...but I cant find anything written on bypassing the sensor.
Lemme find you the pic you need...
EDIT::::
here we go
Okay now the explanation:
see that little circle in the bottom right of the pic? That's your photo cell. What that wire is doing is bypassing the photo cell, so your cluster WILL NOT dim. There is not further instructions needed. If you just solder a small wire exactly like that, that's all there is to it. If it works, you found your problem. You should be fine just leaving it go if it works. If you experience the same problem, the wire is simple to remove.
Oh- BTW, you're '85 DOES have the ambient temp sensor. But the problems you describe do not point to that ground as being a problem. If you would like to see where that sensor is, lower your drivers side lower dash panel, and in the front at the firewall you will see the interior side of the Ambient temp sensor....
Last edited by mikey whipreck; Dec 19, 2004 at 09:56 PM.
Thread Starter
Instructor
Joined: Aug 2004
Posts: 155
Likes: 0
From: CA
Originally Posted by mikey whipreck
Lemme find you the pic you need...
....
....
.... To defer pulling the dash out..I spent some time in the engine compartment and under the car or looking for loose or missing bell housing grounds etc (per my dash repair book)...and couldnt find anything looking particularly wrong...actually, couldnt find much of anything period cuz it is so tight in there (no black and white striped wires to be seen). Hopefully it is not particularly ground related. The former owner told me about a dash problem that he "fixed" right before selling me the car...(and gave me his dash repair book for reference). My guess is that it probably is the same intermittent problem.
Thanks again for all the help...Happy Holidays!
