Temperature Gauge problem

ladiacos · Post by **ladiacos** » Fri Jul 15, 2016 3:40 pm

I've just put power to my M38 project and as expected there were a few issues to sort out but the one problem I cannot figure out is why my Temp gauge goes to 260 right away. The engine has not run and there is no coolant. You cannot cross the wires. The gauge is not new but the sensor is and either could be bad but I would like to make sure I am not doing something wrong. Anyone out there know about this problem. Is it the gauge, the sensor or reversed something.

Richard

4x4M38 · Post by **4x4M38** » Fri Jul 15, 2016 5:11 pm

Richard,
It sounds like the wiring to the sender is questionable or you have a bad ground. Or the sender could be bad.

We have all of the gauge troubleshooting right here on the website.
Look under downloads.

Take care,
Brian

Post by **wesk** » Fri Jul 15, 2016 10:43 pm

Richard,

The first thing you want to do is write down the Part # of your gauge and sender. Then open your Parts Manual ORD 9 SNL G-740 and confirm you have the correct match. Early sender with early gauge or late sender with late gauge. If you don't already have a ground/bonding strap attached to your instrument cluster and the firewall put one on there now.

Then go to the downlaods section under M38/M38A1/M170 and electrical and download this Tech bulletin:
http://www.willysmjeeps.com/v2/modules. ... tit&lid=46

ladiacos · Post by **ladiacos** » Sat Jul 16, 2016 6:35 am

Thanks gents. I went looking through all my parts and luckily found the old sensor and it does indeed have a different part number. I tried it and the needle advanced only slightly. So here is to hoping that was the problem and it is still good. I think the new sensor may still be good but it won't work with my gauge. I will also ground my gauge cluster as advised. I could have been swapping out sensors and chasing ghosts until doomsday had I not come to this site. I have downloaded all the recommended info.

Again
Thanks
Richard

Post by **wesk** » Sat Jul 16, 2016 9:04 am

Another tid bit of info Richard. Leave the paint off the contact surfaces between the instrument cluster and the gauges and the instrument cluster and the gauge retainer clamps and finally between the instrument cluster and the three lamp bodies.

Same goes for other obvious grounding points and the chassis / body/ engine.