Temp gauge not working

[72hoopti]

Gauge is working!!!!!! Got into the harness because I realized I had no continuity through the wire. Someone had gotten into the harness and cut the wire. Idiots!!!!
Spliced wires back together, check for continuity and sure as heck, gauge works. Sending unit is perfect, as the gauge gets to the first hash mark and stays put. The harness is taped and looks sweet going up the firewall. Thanks for all the advice.

Just for reference-the gauge is not grounded to the cluster(see above) and I Teflon taped the sending unit. Just my two cents...

[Burgie70]

I went through two sending units from Napa before getting one to work. Gauge would always read low temp but was getting good heat out of heater. It homes in on mid range now but upon warming up it gets close to the red then backs down. Maybe the thermostat is playing games. LOL

[BruthaMan]

Managed to get the temp sending unit from Lectric Limited installed this weekend. Took a few photos:







Looks like a normal sending unit. We did some test and tune today and finally had a chance to test it out. Worked like a charm! Was able to drive the truck around quite a bit and the temp gauge stayed at the half way point between cold and center.

Prior to this, the gauge would always go from cold to full heat in ten minutes or so, as if overheating. Temp gun, while tuning and after about fifteen minutes of running, showed 178 in the radiator.

[bigmac73]

Originally Posted by 72hoopti

Does anyone remember what color wire runs to the tem sensor? I have assumed it was a green wire but have no continuity from green wire on sensor to green wire in plug that goes into back of cluster.

HELPPPPPP!!!

if you have no Continuity ?? then you have found the problem
chase the wire back through the firewall maybe there is a bad connection in the bulkhead connection

[cppursell]

Just wanted to say, I had the same problem with the gauge maxing out all the time, and when I grounded the bottom post it worked! I'm not sure about accuracy yet, but when it's cold it shows cold, and rises when the engine's warming up!

Thanks for all your tips.

[davepl]

Originally Posted by Bryan H

Have you replaced the 2 4amp fuses at both front fenders in the wiring harness? I had 1 blown, replaced it, and my gauge works fine now.
Posted via Mobile Device

Sorry, this is new to me. Does anyone know what this means? Are there fuses somewhere in the factory wiring harness?

I appear to have no continuity between the sender and the left (facing the back) of the temp gauge. I've got 671 ohms at the sender at room temp. It seems completely open between the gauge post and ground though... which makes me wonder about this fuses, but I don't know where to look.

Thanks,
Dave

[67chevemall]

Originally Posted by davepl

Sorry, this is new to me. Does anyone know what this means? Are there fuses somewhere in the factory wiring harness?

I appear to have no continuity between the sender and the left (facing the back) of the temp gauge. I've got 671 ohms at the sender at room temp. It seems completely open between the gauge post and ground though... which makes me wonder about this fuses, but I don't know where to look.

Thanks,
Dave

No he posted while burning one and was taking about the Amp gauge not the temp gauge. No fuse on temp gauge wire....

just ground the sending wire on the engine and see if the gauge moves....great place to start

[timski69gmc]

Yep, I will chime in as well.
Picked up a tach cluster in the spring, and when I put it in, everything seemed to work fine except for the temp gauge, which went to max with the key on. The old one was functioning well, so figured the sending must still be good. Tied in a ground on the bottom post to the dash, and voila! Gauge read cold, and went up as it warmed. Didn't have it running long enough to see how high it climbed, but should be fine.
Thanks guys!

[Ole Greenie]

Originally Posted by 67swb72klb

no the ceramic resistor was bad in my case
good luck

Is there a vendor for the ceramic resistor that you have found?