Jared Richey Posted June 10, 2015 Share Posted June 10, 2015 I will save the long story for later, but here is what is going on. I have upgraded to tach and gauges, and a rebuilt wiring harness for factory tach and gauges. My temp Gauge is new from sonny94 on ebay, I have a new sending unit in the engine for a Gauge. Their is power to the gauge, and it will move, when you crank car it goes over and comes back kind of like my new Tachometer does. But I drove the car around today and it does not move off of 100 while running. Are there something different between the fuse block and the sending unit on an original idiot light car possibly causing it not work? My dash harness is tach/gauge, sending unit in engine is for gauge, and has power. My UNDERHOOD Harness is original to the car. Other problem. When I pull park lights on Dash Lights do not come on. THERE IS NO POWER to the "LPS" terminal on the fuse block, so of course the dash lights or anything wired to it is not working. What could cause this? A mistake made in the wiring harness, something wrong with the headlight switch? If there is something wrong, and the headlight switch is not the problem, how could I simply bypass the problem and make the dash lights work when I pull the parking lights on. I know they can be straight wired to 12 volts, then they would burn all the time, or on a toggle switch but after all of the work I have done, I want them to work correctly. Quote Link to comment Share on other sites More sharing options...
monte70car Posted June 10, 2015 Share Posted June 10, 2015 Jared use a 9volt battery across the temp gauge this will cause the needle to move, if it doesn't move then it could be a bad gauge. As far the bulkhead connection, I believe the wires are in the same place for a light dash and a gauge dash just the pin lay out is different. I'm currently wiring the 72 with an American Autowire kit and notice they don't use the two brown wires for the amp gauge. On the dash light you stated there is no power at the fuse, how does the connection that the glass fuse look like? There should be power on one side of the fuse even if it's blown. The headlight switch gets its juice from the lamps fuse if there is no juice at the fuse the headlight switch wouldn't be the problem unless you have juice at the fuse. A few years back I brought a power probe which has come in handy for testing different items in the elec system. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted June 10, 2015 Share Posted June 10, 2015 I'm pretty sure the plug that connects to the cluster has to have a few wires moved in the connecter Quote Link to comment Share on other sites More sharing options...
Jared Richey Posted June 10, 2015 Author Share Posted June 10, 2015 There is no power at the fuse block at all, and none is going there. It's a grey wire that feeds that terminal Quote Link to comment Share on other sites More sharing options...
monte70car Posted June 10, 2015 Share Posted June 10, 2015 Jared sounds like a broken wire on the back side of the fuse holder. Quote Link to comment Share on other sites More sharing options...
Jared Richey Posted June 10, 2015 Author Share Posted June 10, 2015 I've checked that, it's good. Quote Link to comment Share on other sites More sharing options...
Jared Richey Posted June 11, 2015 Author Share Posted June 11, 2015 Got power at temp gauge and temp sending unit and good grounds, still temp reading still need to figure out where the grey wire from the fuse box leads to and that will probably figure out why they are not working. I wish I had a good wiring diagram that I could actually read 1 Quote Link to comment Share on other sites More sharing options...
Jared Richey Posted June 11, 2015 Author Share Posted June 11, 2015 *No temp reading Quote Link to comment Share on other sites More sharing options...
Rock Posted June 11, 2015 Share Posted June 11, 2015 Curious....Can you put a meter on the sending unit and watch the out put change as the engine heats up? Also can you ohm the sending unit wire from the block to the dash? Is there continuity? Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted June 11, 2015 Share Posted June 11, 2015 Jared, pull on your lights, then check for power on the gray wire, gray is usually for some dash/console/heater lights, it won't have power unless the lights are on Quote Link to comment Share on other sites More sharing options...
Jared Richey Posted June 11, 2015 Author Share Posted June 11, 2015 Well I solved the no power on the LPS terminal issue, it was a Bad rheostat on the headlight switch. Luckily I had bought a new one, but after the nightmares on the 57 with new ones, I used a used one, and it was bad. Installed the aftermarket swich and now have power to the dash LPS. Now to figure out the Temp Gauge. Quote Link to comment Share on other sites More sharing options...
my72toy Posted June 12, 2015 Share Posted June 12, 2015 Here is what I would do next. Unplug your wire from the temp sensor and use an OHM meter and go between that wire and the wire in the #10 position on your cluster plug, which should be a dark green wire. You will have to make up some sort of an extension lead for your meter as I assume the leads will not be long enough. If it ohms out to about zero, then you know the wire does not have any breaks in it and also you know you have the correct wire going to the cluster plug. Would suggest unplugging the cluster plug when doing this. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted June 12, 2015 Share Posted June 12, 2015 Did you use Teflon tape or pipe dope on the sending unit? if so the sending unit might not be grounding, seen this happen many times, if grounding the wire to the sending unit makes the gauge move, try using a wire to ground and touch the sending unit and see if the gauge reads then 1 Quote Link to comment Share on other sites More sharing options...
Rock Posted June 12, 2015 Share Posted June 12, 2015 Curious....Can you put a meter on the sending unit and watch the out put change as the engine heats up? Also can you ohm the sending unit wire from the block to the dash? Is there continuity? Here is what I would do next. Unplug your wire from the temp sensor and use an OHM meter and go between that wire and the wire in the #10 position on your cluster plug, which should be a dark green wire. You will have to make up some sort of an extension lead for your meter as I assume the leads will not be long enough. If it ohms out to about zero, then you know the wire does not have any breaks in it and also you know you have the correct wire going to the cluster plug. Would suggest unplugging the cluster plug when doing this.longer version of what I said. Quote Link to comment Share on other sites More sharing options...
Jared Richey Posted June 14, 2015 Author Share Posted June 14, 2015 I found a 70 chevelle engine harness diagram and I have the green wire hooked to the gauge that goes to the TCS switch that's mounted on the wire holder. There is supposed to be another dark green wire that runs through the fuse block, I have not located yet, I would assume I need the one going through the fuse block. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted June 14, 2015 Share Posted June 14, 2015 the green wire for the temp gauge should be in the harness going towards the core support, not in the engine harness Quote Link to comment Share on other sites More sharing options...
Jared Richey Posted June 16, 2015 Author Share Posted June 16, 2015 Got this fixed now, I mistaked the do hick on the other side for the temp sender. Anyway I just left my gauge sender there and run the green wire over there. Poof works perfect. It had been a while since I messed with the idiot light, why they had 2 things that looked like a temp gauge I don't know maybe the old TCS something. Quote Link to comment Share on other sites More sharing options...
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