72MonteCarlo Posted October 3, 2016 Share Posted October 3, 2016 The Flexible circuit board behind my gauge cluster keeps burning up. I'm on my 3rd circuit board and I can't figure out what keeps making it burn up. I've looked at the fuses and there was a 15A fuse in the gauge spot and it was supposed to be a 10A there so I went ahead and replaced all the fuses and put the 3rd circuit board in today and it started to burn as soon as I put it in and when to crank it. I can not crank it without this circuit board so I need to figure out the problem. 1 Quote Link to comment Share on other sites More sharing options...
Rock Posted October 3, 2016 Share Posted October 3, 2016 You have something that has a dead short. Can you follow which trace is opening up? Or is it multiple traces? B est way is to get out the ohm meter and look to see what is shorted to ground. Quote Link to comment Share on other sites More sharing options...
72MonteCarlo Posted October 3, 2016 Author Share Posted October 3, 2016 There is only one spot on the circuit board that is burning up if that's what you mean. Other than that I really wouldn't know how to check and see what's causing it without tearing apart the car. Quote Link to comment Share on other sites More sharing options...
MCfan Posted October 3, 2016 Share Posted October 3, 2016 Robert, I am strongly suspicious that your circuit board is being grounded by its outer edge touching some metal or exposed wire in or around your dash frame or instrument cluster housing. When you hit the ignition to crank the motor, you pass through the Accessory On position which provides positive voltage to the circuit board and one of the circuit paths is grounded (shorted to ground) so it goes up in smoke. Even a 10 amp fuse will not blow before those foil-thin copper ribbons in the circuit board incinerate. I actually destroyed one by accidentally touching the edge with a needle point pliers when trying to seat the clock connector on the back of the instrument cluster. That taught me to disconnect the battery before starting ANY electrical project. I suggest you carefully look for any metal or exposed wire that could be touching the edge of the circuit board when you seat the dash/instrument cluster back in place. I hope Darren (LS5) sees your post because he is an expert on instrument cluster wiring and can probably diagnose your problem better than most. Good luck. Quote Link to comment Share on other sites More sharing options...
72MonteCarlo Posted October 3, 2016 Author Share Posted October 3, 2016 I'll definitely check into that! Thank you! Quote Link to comment Share on other sites More sharing options...
Rock Posted October 3, 2016 Share Posted October 3, 2016 Well if he is on his 3rd circuit board I doubt it is the board itself. I assume something connected to the board is shorted like the fuel gauge, the clock or something like that. That's why I asked what trace was opening up. I would follow that trace and see what it is attached to. If it was the dash lights than the small fuse would of blown before the circuit board. Follow the trace back to the connector and see what that pin supplies. Quote Link to comment Share on other sites More sharing options...
RealRed70 Posted October 3, 2016 Share Posted October 3, 2016 The speaker bracket on the drivers side, behind the cluster can short things out. That bracket was used on cars with A/C, or cars with a stereo radio. Also the Amps gauage is known to have burned up plenty of printed circuit boards. Quote Link to comment Share on other sites More sharing options...
72MonteCarlo Posted October 3, 2016 Author Share Posted October 3, 2016 I'll check that too. As soon as I get a chance today I'll work on it. Quote Link to comment Share on other sites More sharing options...
72MonteCarlo Posted October 3, 2016 Author Share Posted October 3, 2016 The speaker bracket on the drivers side, behind the cluster can short things out. That bracket was used on cars with A/C, or cars with a stereo radio. Also the Amps gauage is known to have burned up plenty of printed circuit boards.So is there a way to disconnect the amp gauge? I looked and thats where it's burning up at. Quote Link to comment Share on other sites More sharing options...
lastss Posted October 3, 2016 Share Posted October 3, 2016 There's a Safeway to eliminate the amp gauge, which is always a fire hazard. Replace with a custom made volt quage on eBay 105. Shipped. I'm going to get one. Has both green & white. 1 Quote Link to comment Share on other sites More sharing options...
RealRed70 Posted October 3, 2016 Share Posted October 3, 2016 You can eliminate the Amp gauge by removing the black wire with a white stripe and the solid black wire from the connector that plugs into the back of the printed circuit board. They are in locations #3 and #4 in that plug. Wrap them up well with electrical tape. They could also be removed from the fuse block if that seems easier for you. They are in locations C-X and D-X in the fuse block. Do not cut them out remove the terminals from the plug or the fuse block in case later a person wants to set things back up as they were from GM. Quote Link to comment Share on other sites More sharing options...
Rock Posted October 3, 2016 Share Posted October 3, 2016 I have thinking about replacing mine with a voltage gauge. Quote Link to comment Share on other sites More sharing options...
Murphy Posted October 4, 2016 Share Posted October 4, 2016 Go with a VOLTS gauge, eliminate the problems with high amps in your dash. When I converted from indicators lights to gauges, the wiring issues were cut in half by converting to a volt gauge. Call Gary "the tachman" for the conversion. Quote Link to comment Share on other sites More sharing options...
stangeba Posted October 4, 2016 Share Posted October 4, 2016 I was also going to mention, like above, a left ft speaker / bkt shorting it out because mine almost did! Bruce Quote Link to comment Share on other sites More sharing options...
KLASSIK1 Posted October 6, 2016 Share Posted October 6, 2016 Bruce is correct from the factory they put a piece of electrical tape at the edge of the housing to keep it away from the speaker bracket Leo Quote Link to comment Share on other sites More sharing options...
72MonteCarlo Posted October 7, 2016 Author Share Posted October 7, 2016 So far it looks good after I disconnected the Amp gauge Quote Link to comment Share on other sites More sharing options...
RealRed70 Posted October 7, 2016 Share Posted October 7, 2016 I am glad that that worked out for you. Quote Link to comment Share on other sites More sharing options...
AnHie65 Posted November 21, 2016 Share Posted November 21, 2016 Another vote to left speaker, see the picture. Quote Link to comment Share on other sites More sharing options...
AnHie65 Posted November 21, 2016 Share Posted November 21, 2016 Dear friends, What do You recommend as a good place to buy this flexible circuit board? In Rockauto it is out of stock... And I do need some web shopping due to the fact that this is needed to deliver to Finland, Europe. Thanks, Anssi Quote Link to comment Share on other sites More sharing options...
RealRed70 Posted November 21, 2016 Share Posted November 21, 2016 I get them from sonnie24 on ebay. Here is a link for the printed circuit board. http://www.ebay.com/itm/70-71-72-1970-1972-CHEVELLE-SS-EL-CAMINO-MONTE-CARLO-CIRCUIT-BOARD-GAUGE-CLUSTER-/371783816046?hash=item56900ad36e:g:JtIAAOxyLN9SodGX Quote Link to comment Share on other sites More sharing options...
AnHie65 Posted November 21, 2016 Share Posted November 21, 2016 I get them from sonnie24 on ebay. Here is a link for the printed circuit board. http://www.ebay.com/itm/70-71-72-1970-1972-CHEVELLE-SS-EL-CAMINO-MONTE-CARLO-CIRCUIT-BOARD-GAUGE-CLUSTER-/371783816046?hash=item56900ad36e:g:JtIAAOxyLN9SodGX Thanks, I found another one with no tach (as my need): http://www.ebay.com/itm/330883652050?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT Anssi Quote Link to comment Share on other sites More sharing options...
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