I had been doing some work in my dash and the last time I used my car my temp gauge was working. Now when I turn the switch on it gets power but it goes all the way up past the H. Anybody know what might be causing this? It seemed to work just fine the last time I drove it. Thanks!

 

had the same thing happen to me. Ended up having to replace the gauge. Actually ended up replacing all my gauges with aftermarket gauges since my oil pressure, fuel, and speedo didn't work right either.

However if it worked before you messed with it, I'd go back and check that you didn't knock any wires loose. Pretty sure a bad ground would do the same thing.

 

switch on ignition
disconnect your water temperatur sensor cable at intake manifold (check what gauge reads when you do that)
connect the wire that was at sender to engione block (blank spot) so you get ground on that (check what the gauge reads there).
If it goes from hot to cold doing this test then the sensor is dead.
if that doesn't help you'll have to remove the cluster again to check

 

Chances are something is just grounded out, do the checks that are mentioned also depending on the application the two posts coming off the gauge itself can become grounded to the back of the gauge cluster.

 

If you need a new sending unit find a Ford one, the aftermarket units are notoriously erratic.

 

Thanks everyone, I'll check those when I work on the car next. If I end up getting a new gauge I'll make sure it's a Ford one, thanks for the tip! I'm hoping it's just a ground problem, but we'll see!

 

if it's not the sending unit thenI'd say as well chances are that one of the wires going to gauge is grounded out

 

Thanks for everyone's responses. Finally got back into the dash and found out the ground nut had come loose and there wasn't a good connection there. Thanks again!

 

Kool, glad you got it fixed.
Just to set the record straight: the stock gauges will go to their lowest values if the line to the sensor is shorted to ground (below E or C). If the line has high resistance, (like a wire fell off or loose nut or bad sender unit) it will go to the F or H positions (and typically above)

 

i never know which way around it is. I always think that this is the wrong way around.
if a wire comes loose the thing shoukld go to full hot. scares people, they get it fixed.
if it's at cold, some people dont care, the other half dont realise something is wrong.
the amount of times I've seen overheated engines with blown gaskets where the owner told me that the gauge didn't work ... last one I am fixing at the moment. a 429 torino where the rad cap was forgot to put back on. engine is mush, so now a 460 is going in. that 429 is scrap :-(