Hey guys...

I've installed the oil temp gauge on my 07 streetglide in place of the worthless air temp gauge. The temp sending unit is mounted to the oil pan. I've noticed that at times the gauge is pegged. A quick tap with the finger and the gauge moves back to more what I expect the temp to be.

How do you go about trouble shooting this?

Is there a way to isolate what the bad part is without having to buy a whole new gauge?

I'm kinda of the belief the problem is with the gauge itself since tapping it with a finger "corrects" the problem.

 

did you put teflon tape on the plug in the drain pan?? it might be your ground

 

Possibly a ground problem - get all that teflon tape off if there is any and see if that helps. Next try switching the power source to a different location. Mine was erratic and I found out it was getting interference from an aftermarket brake flashing unit. Dealer moved power source off of the brake circuit and it works fine now. I'd try easy stuff like this before actually swapping out the gauge or sending unit.

 

I would lean toward that as the cause too. Check your connections at the gauge for tightness, although I think a direct short is causing the gauge to peg as described. If you have the HD gauge there is no problem with using Teflon tape on the sender threads since it has a separate ground wire, but if you have the McEwan gauge you should not use it. It's not necessary anyway and there is a chance of getting bits of tape in the pan and finding their way to the wrong places.

IIRC pegging the gauge means a direct short in the sender circuit, as if you lose the ground or sender connection it will peg toward the zero end. On the HD gauges the small circuit board is at the rear of the gauge and exposed, so if your wrench slips while installing and it damages the traces you may have an inoperable gauge. Since it's sporadic I doubt if that's the cause, but like you I would put my money on a short inside the gauge.

 

It's the HD gauge. I don't honestly remember if I used teflon tape on it. I'll double check. I realize this may not be necessary, but is worth checking.

 

Does anyone know where I can find a replacement sending unit? It seems like it would be a common thing... Would Napa have something like this?

I appreciate the input!

 

Don't bother checking, as it doesn't matter one way or the other. Just make sure none of it gets loose and starts floating around in the oil flow. Napa does carry this adapter, #3220 x 6 x 2 (1/8F-3/8M).

 

Ditto what iclick said... It's shorting out direct to ground.