There are four stamped nuts that hold the speedometer to the dash.
I think they are 5/16, The studs they run on (which are part of the dash) are kinda long. I usually use a 'nut driver' to break the nuts loose. After I get them backed out a little, I can usually use my finger to spin them the rest of the way off.
They are located at 2 0'clock, 4 0'clock, 8 0'clock, 10 0'clock
It is a royal pain to do,
If you do take the dash loose, I would suggest only pulling it out a few inches (I would rather deal with the tight pain I mentioned first, than to compound things by taking the dash loose!)
A hand mirror and lighting behind the dash, may help in doing the task.
Normally when there is a temperature gauge problem, the fuel gauge, which has the constant voltage regulator (CVR) built into it, [this provides about five volts to operate both the fuel and temperature gauges] Is usually presenting problems also.
If the fuel gauge works fine, either the temperature sender is bad/or disconnected (purple wire on cylinder head). Seldom have I seen a bad temperature gauge. (They usually barely move, may be mistaken for being bad)
Most of the time it is the fuel gauge presenting the problem, which affects both.
You can test the gauge by taking the purple wire off of the sending unit, stick a nail inside the connector and ground it to a good ground (you can use a alligator clip jumper wire too)
While it is grounded, the gauge's needle will sweep to full hot, confirming the gauge is okay.
Let me know what you find.
Or any more questions.
Images (Click to enlarge)
Monday, June 26th, 2017 AT 6:54 PM