hello im starting to put my car back together and i did the dash and cluster today everything works except for my temp gauge everytime i turn the ke to start the car the needle jumps off the reading and gets stuck there i tried to unhook the green wire from the head and try it but same thing. the engine is a lt1 vett engine and the sensor is on the passenger side were on my 305 it was on the drivers side. this motor has one on the drivers side too but is for a 2 wire plug not a single. any help would be great its a 85 z28 carbed

 

Green wire might be "open"???

 

sorry but what does that mean and how do i check for that. thanks

 

You'll have to check for continuity, meaning No break/cut/open, on the green wire.

Here's a pinout of the cluster connections for a 1986, same as an '85

https://www.thirdgen.org/forums/atta...er-pinouts.jpg

Also, the contacts on the cluster where the two connectors mate are very fragile especially for their age. If you take cluster out again check the contact at C2-7, it may be your problem.

 

For some reason GM wired in a bulb check to the gauge. So when you start the car the gauge will peg. My 86 does the same thing, I looked at the shcematic a while back and noticed this.
Was some time ago, so will check out the schematic later and let you know if theres an easy way around it.

 

Hera ya go:


Dk/Grn wire, the one that comes from the sender. Under tha dash its hooked into the Igintion switch via connector C100.
C100 just says "Left Hand Side of Dash" We/You need to cut that loose from the swtch.
Wish my disk would show C100 and all the wires on it. Would make life easier.

Anyway, hope that helps.

 

Your gauge is physically stuck to the black gauge bezel under the plastic lens.


Remove the plastic lens and the bezel and it will come unstuck. Then bend the gauge down slightly or bend the bezel in such a way that it doesnt get hooked.

 

It feels like it was just yesterday someone asked this question...

https://www.thirdgen.org/forums/cool...icks-past.html

 

my 86 did the same thing, chased wiring for a bad temp gauge, when you turn the key on its shorted to ground(no resistance) so it pegs hot but then comes back to the resistance from the sender, if it had an open(infinite resistance) it would peg cold. check that the needle isnt sticking and replace the gauge if it isnt.

 

That was yesterday for old people.... o/ o/ o/ \O