[swilk]

I just bought a 68 SS with factory gauges ... and cant get the temp gauge to work. I have installed a new sending unit with no luck. Whenever you starte the car, the gauge does go to the coldest position ... but it just stays there. What is the path of the circuit? How often do these gauges go bad ... and is a replacement available? Thanks for any help you can give.

 

[68KMENO]

the sending unit is the ground ... as you've said the guage zero's out when power is applyed I'd say the sending wire isn't making contact or is broken ... quick check disconect wire from sending unit an put jumper wire to it & a good ground ... should send guage up if not wire is probley broken check with ohm meter

 

[swilk]

Well, after working for a few hours last night on the problem ... this is what I found. When I grounded out the wire, the gauge went to HOT .. so the wire looked good. Tried all kind of things .... then late last night while watching TV it hit me ... when I installed the new sending unit, I wrapped the unit in teflon tape. I would say that the tape is keeping the unit from grounding ..... Anyway, Ill remove the tape this evening and see if it was just a bad sending unit from the begenning.

 

[supersport396_2000]

I wrapped the unit in teflon tape. I would say that the tape is keeping the unit from grounding

Yep,i've done that too,its like DUHHH when you realize what you've done

 

[68KMENO]

yep

don't you just hate it when that happens ...oh well your not to first person to have GROUND problem ... (that is why my reply started with the SENDER is GROUND) most of the problems I've seen while answering questions on this board are ground related at least you figured it out before buying new guages !!!

 

[swilk]

Well, I have come to the conclusion that it is the gauge that is bad. Even after remiving all teflon .. .the gauge still does not work consistantly. It works VERY intermittantly .... I dont know what else to try. I have tried 3 sending units, re-wired fron the firewall to the sending unit ..... ran a totally seperate wire fron the unit to the gauge ... nothing. I still might have grounding problem, but I dont see how ... battery ground goes directly to passenger side head and there is a ground strap from the drivers side valve cover to the firewall. Anyway, is there a replacement gauge available and if so ... from where?

 

[John_Muha]

Before you send the gage out for repair, there is a possibility that the calibration resistor is bad. It’s that white ceramic block on the backside. The gage doesn’t quite act like a bad resistor but worth a shot. Find something like a late 70s pick-up truck with a temp gage and take one off of it. They are all pretty much the same.
There are places that repair gages but I don’t have a link with me right now.

 

[68KMENO]

I don't know about a new guage being avaible ... but I have used Redline gauge & clock repair in Tennessee 1-731 661-0239 call them

first tho did you clean all the junk out of the threads where the sender screws in?? I mean like with a small wire wheel down to bare casting ?? & did you check & clean the power supply line to the guage ?? Intermit problems are the hardest to track down... taking the dash out & apart isn't much fun

 

[swilk]

Is the + voltage wire just a switched 12V+ ? I have not traced this wire .. nor have I ensured that it was giving a good and constant signal. I will try this before I do anything else.