Temp Gauge Always Maxed

Looking for some direction. Recently purchased a 87 S4, which is in dire need for some TLC. In order to get it passed inspection (in MD), I had to replace the CV joints, replace a front cracked headlight, fix parking brake and get the reverse lights working:eek:. Also had TBF issue checked.....thanks for the suggestion.

Now on to a very important item. When the car is cold and off the temp gauge is in the down postion. One turn of the ignition an it shoots to the max postion and stays even after I shut it off. Looking to diagnose the issue.....is it the gauge or would it be the temp sensor?:confused:

Unrelated anyone subscribe to www.alldatadiy.com/index.html for step by step repairs? I was considering. Thanks randy

I am not sure but normally when you pull the gauge temp wire off it will go full one way or the other and when you ground it the opposite of when it is off.

I think that there may be 2 temp senders, again not sure, so you should check the manual for which sensor controls the gauge.
Then remove the wire and see if it make a difference with the key on and then ground it with the key on.
This will tell you if from the wire to the gauge is good.

If it goes full left or right during this test then you know that it is a bad sender.

If nothing happens then you will have to test closer to or even at the gauge

Some one who knows more should chime in shortly and if not then I will walk through the manual with you.

Brad

I vote for a faulty resistor. Pick up a new sensor. They're not expensive and simple to replace. If that doesn't do it, report back and we'll go into further detail about the circuit so you can accurately troubleshoot it.

okay - will go the replace sensor route 1st. anyone have the step by step for this?