I have a 1988 Trooper II. When I start the thing up, the temp gauge immediatley goes to the max reading, and after I turn the car off, it slowly goes back down. This seems weird to me, because by my understanding and experience, if its not working, it shouldn't work at all, and should have no reading whatsoever. Can anybody tell me where the temp gauge sender is in the engine compartment or any other usefull tips? Thanks.

sounds like the sending unit is toast.

the troubleshoot test procedure is to unplug it and ground it with a jumper wire, key on and if gauge pegs 'H' you know the sender is at fault. if it did absolutely nothing then you'd have to inspect the wiring & connection. so half your work has been done already.


cost $10-$30 depending on source, many cars use the same sender so look around.

check out this pic:
www.marcuccimotorsports.com/trooper/manifold/manifold1.jpg

see the 2 circles?

the upper one is for the temp gauge sender. and fyi the one below it is the temp sensor for the ECU.

Wait, this isn't correct. If you pull the wire off the sender and then ground that wire and turn the key on, you have given the gauge a perfect ground, it should show full hot. This is more of a test for the gauge and related wiring, not the sending unit.

Sounds like your best test would be to unplug your sending unit and turn the key on (making sure you don't ground the end of the wire against the block). If you still go to full hot when you turn the key on you have a wiring issue. I'd be looking for a ground in the sending unit wire.

If the ungrounded test does not make the guage go to full hot then ground it. If now it does go to full hot, change the sender.

You can get a sending unit for about 20 bucks or so.

Joe

Ok, I went and messed with it today and I remembered that when I replaced my head gasket I broke a wire that went to the intake plenum. At the time I thought that the wire was a ground, so I just bolted the bare wire back on to the plenum. I disconnected that wire today, and the gauge showed nothing. So i'm thinking now that the wire is not a ground (obviously), and that I need to find the connector on a junker and splice it in. What do you think, will that work if i just splice it in with a little crimp connector and some electrical tape?

Best thing to do is solder it, but you shouldn't have a problem with that. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Richard <img src="/forums/images/graemlins/patriot.gif" alt="" />