monte70z20 Posted June 20, 2016 Share Posted June 20, 2016 I had posted to my last gauge cluster question so apologies for repeating my question: Before I put the dash back in, I want to check the gauge cluster to see that everything is working. Electrical is not a strong point for me so I was wondering what it would take to just plug the gauge cluster into the wiring harness without the dash in place to see that everything works. Is this possible? From reading other posts it sounds like making sure everything is grounded is a priority. Any specifics much appreciated Quote Link to comment Share on other sites More sharing options...
cbolt Posted June 20, 2016 Share Posted June 20, 2016 If you are concerned about grounding, just connect a jumper wire from one of the bolt mounting tabs on your dash to its corresponding tab on your vehicle body. That should ground the dash assembly sufficiently to allow you to test everything. Quote Link to comment Share on other sites More sharing options...
monte70z20 Posted June 20, 2016 Author Share Posted June 20, 2016 cbolt, the gauge cluster is separated from the dash. I just want to plug the cluster in without attaching it to the dash. Quote Link to comment Share on other sites More sharing options...
monte70car Posted June 20, 2016 Share Posted June 20, 2016 So you can plug the cluster in and it will light and show what's working, just make sure you have the grounds grounded. Quote Link to comment Share on other sites More sharing options...
cbolt Posted June 20, 2016 Share Posted June 20, 2016 What he said Quote Link to comment Share on other sites More sharing options...
stangeba Posted June 21, 2016 Share Posted June 21, 2016 So you want to verify all the tiny bulbs that light up the instrument cluster are working. I don't know how to do that but you will need a good ground. Was there a problem with them all or some? I believe many IP light problems are related to the HL switch or bad ground. Many replacement HL switches are WRONG! I tested each bulb separately, with a 9V battery but many were dark (on the inside) so I replaced them. Good luck, Bruce Quote Link to comment Share on other sites More sharing options...
monte70z20 Posted June 21, 2016 Author Share Posted June 21, 2016 stangeba: When I bought the car, None of the gauges were working, and speedo was not connected. When I took the dash out, I could see that "metal strip" I referred to in an earlier post was not connected and there is a homemade wire connected to one of the posts on one of the small gauges (Can't remember which gauge and car is at my buddies shop right now). I believe it is the gauge above the light switch that this wire is attached to. Also, one of the wires in the main harness is deliberately cut and I'm not sure why. I replaced the circuit board, Lastly, I'm missing 3 of the little black light sockets (anybody know where I can get these?). While I have it apart, I'd like to see if I can get everything sorted out and working. 1 Quote Link to comment Share on other sites More sharing options...
stangeba Posted June 21, 2016 Share Posted June 21, 2016 Power goes through the AMP gauge. A poor design as power demands grew in newer vehicles. Is it still an AMP gauge or was it changed to a VOLT gauge? Sounds like many things were worked on by the previous owner. Part of the fun of an old vehicle! I wonder if the car came from the factory with the gauge package or the previous owner tried to add them? Good luck! Bruce Quote Link to comment Share on other sites More sharing options...
monte70z20 Posted June 22, 2016 Author Share Posted June 22, 2016 From the condition of the cluster and original circuit board, it looks like a factory cluster. It is an AMPS gauge that the wire is attached to. I have attached pictures of the gauge, the wire connected to the gauge and the cut wire on the harness. Any ideas what the cut wire on the harness was for and why the wire on the AMPS gauge? Quote Link to comment Share on other sites More sharing options...
monte70car Posted June 22, 2016 Share Posted June 22, 2016 Is that wire going off the amp gauge going to the grounding plate for the headlight? if so it shouldn't be there. If you can provide the colors on the plug for the cluster I can verify what they are. Looking at the plug the one that is broken looks to be a dark blue so it might be oil pressure. The AMP wires black and black with a white stripe. Quote Link to comment Share on other sites More sharing options...
John S Posted June 22, 2016 Share Posted June 22, 2016 Sometimes the printed circuit will burn going to the Amp. gauge, after all they are just thin copper. Sometimes a person will hook up jumper wires from the harness to the gauge and bypass the printed circuit. I did that to my Monte in 1980 so I would not have to replace printed circuit. John S Quote Link to comment Share on other sites More sharing options...
RealRed70 Posted June 22, 2016 Share Posted June 22, 2016 Is that a black wire that was cut? If so, it was for the amp gauge. Quote Link to comment Share on other sites More sharing options...
RealRed70 Posted June 22, 2016 Share Posted June 22, 2016 They just used a jumper wire to bypass the printed circuit board that was most likely burnt. Quote Link to comment Share on other sites More sharing options...
stangeba Posted June 22, 2016 Share Posted June 22, 2016 I believe this is a great article and talks about this AMP gauge type problem. My charging system is not working today................ LOOK OUT!!!!!!! http://www.madelectrical.com/electricaltech/amp-gauges.shtml Quote Link to comment Share on other sites More sharing options...
monte70z20 Posted June 23, 2016 Author Share Posted June 23, 2016 The wire is attached to the AMP gauge but was not connected to anything when I took the dash out. The circuit board was a mess on this side of the cluster so I would agree that the previous owner was attempting to bypass the board. I'm going to remove this wire now that I have a new board. I have attached a picture of the harness plug and it is a dark blue wire but upon closer inspection it looks like the wire might have been put there. Not sure if you can see in the picture but it is in with a gray wire and it looks like there was a wire there at some point and now this one shoved in there. This wire was also not connected to anything when I took the dash out and I could not see any wires cut along the group of taped up wires connected to this harness. Great article Bruce...added to my Favorites, Thanks! Quote Link to comment Share on other sites More sharing options...
monte70car Posted June 23, 2016 Share Posted June 23, 2016 That gray wire is your dash lights. If that wire is cut you will not have any cluster lights or a/c control panel lights. Quote Link to comment Share on other sites More sharing options...
RealRed70 Posted June 23, 2016 Share Posted June 23, 2016 Here are some instructions on how to test gauges before installing them. Chevelle gauges are the same as Monte Gauges. Quote Link to comment Share on other sites More sharing options...
monte70z20 Posted June 27, 2016 Author Share Posted June 27, 2016 Thanks for all the replies. Can anyone tell me where the two black ground wires hook up to? It looks like they wounld mount somewhere on the cluster. Thanks again. You've all been a great help in sorting this out for me. Quote Link to comment Share on other sites More sharing options...
stangeba Posted June 27, 2016 Share Posted June 27, 2016 I recall one ground wire attached to the parking brake assembly. pic Quote Link to comment Share on other sites More sharing options...
John S Posted June 28, 2016 Share Posted June 28, 2016 I think to the support above steering column. Quote Link to comment Share on other sites More sharing options...
RealRed70 Posted June 28, 2016 Share Posted June 28, 2016 One goes to the steel dash frame to the left of the steering column. Look for a hole in the steel frame. You can see where it attaches in my picture. A black wire also goes to the drivers door jamb switch. Another goes to the headlight switch. Quote Link to comment Share on other sites More sharing options...
monte70z20 Posted June 30, 2016 Author Share Posted June 30, 2016 Hi Everyone: This is a great help. I will go back at it this weekend and hopefully be able to button up the dash and steering column. I believe I have the ground on the parking brake, the light switch and on the door jamb switch but not on the dash frame so I have to put one there. Besides the light switch wire, is there another black ground wire that attaches somewhere else on the cluster? I'm assuming the light switch wire is the one that has the metal strip attached to it. Quote Link to comment Share on other sites More sharing options...
RealRed70 Posted June 30, 2016 Share Posted June 30, 2016 Yes, the headlight switch wire does have the metal strap attached to it. That metal strap also attaches to the wiper switch by two screws. I think that should be all of the black wires. If you come up with an extra black wire attach it to the dashes steel frame in the area where the headlight switch steel strap attaches to. The dash in my picture is out of a 72, so things were wired a little different than a 70. Quote Link to comment Share on other sites More sharing options...
monte70z20 Posted July 3, 2016 Author Share Posted July 3, 2016 Very helpful. I will connect the wire to the dash frame and see what happens. Will post results once I get the dash connected back up. Thanks everyone. Quote Link to comment Share on other sites More sharing options...
monte70z20 Posted July 5, 2016 Author Share Posted July 5, 2016 Well I hooked everything back up today and I am no further ahead. Instrument lights not working, Gas gauge goes past Full, Temp gauge fluctuates wildly and the tach doesn't work. Amp gauge stays at 0 (zero), the clock seems to be the only thing that works. I'm starting to think the car was originally an idiot light car and the owner before me tried to swap it out. I read Dennis' pages on swapping to gauges but couldn't figure out what wires in the harness needed to be switched around or where the wires from the fuse panel connected to in the harness. Has this been posted in the past? Quote Link to comment Share on other sites More sharing options...
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