89straight6auto

I just bought this truck about a month ago. My engine/coolant temp gauge didn't work, (my fuel gauge doesnt either but I'll save that for another thread) so I just bought a universal kit. It works fine. My question is what do I do with the old temp sensor? When I unplug it, the check engine light comes on

jkenprice1

Don't unplug it!! Are you using the original sensor for the new gauge. Can you splice the 2 wires togther.

89straight6auto

No. The new gauge is permanently connected to a mercury filled line that goes into a probe type thing. It screws into the same place as the old sensor into the coolant. I have the old sensor still plugged in but tied off to the side

jkenprice1

I just wondered. Have you tried grounding the wire or grounding sensor.

89straight6auto

No. How do I do that? Thanks

jkenprice1

First i'd try touching the sensor with the wire on it to something metal, like the engine, and see if the check engine light goes out. If that works, try unplugging the wire and touching it to something metal. If that works, find an out of the way strew or bolt you can loosen and put the wire under, then retighten it. You may have tokeep the sensor attached and fasten it to something. Let me know what happens

GhostriderI

My '85 had a fuel and temp. gauge problem the OEM books told me to change the O/P transmitter, O/P was good so I thought it was a misprint, so I changed the gauges, sending units, printed circuit, instrument voltage stabilizer, and troubleshot the wiring and did not fix the problem. When all this failed I changed the O/P transmitter and as if by magic I had both back.

Hope this helps

89straight6auto

What's an o/p transmitter? Where's it located? What does it look like? Thank you, man I really hope it works for mine

GhostriderI

Oil Pressure transmitter (also known as Oil Pressure switch), mine is above the oil filter

Here is a link bottom of the page

http://www.lmctruck.com/icatalog/FD/full.aspx?page=128

89straight6auto

Ok, I have the new o/p switch. I have a couple questions. Do I need to drain the oil before I replace the switch? Im pretty sure this is the o/p switch...(its right behind the dip stick) The bolt/nut I need to loosen to get off is bigger than one inch. Doesn't look like an ordinary shape either..do I need a special tool to get it off? Or is that not where I need to loosen it?