f468357

On my way home from work tonight the fan belt tensioner light cam on and stays on. I took a multi meter to it and it is open in the installed position and closes when I move the arm closer to the switch body. I have searched the posts and have read that this switch is easily removed with one 5mm allen head bold to other who have dropped nuts and have never been able to retrieve them. For anybody who has done this repair is the switch adjustable? If so how? How do you remove the switch from the car? The allen screw? It looks like there are 4 other small nuts that hold the plastic body together and a metal bracket behind that. Any help is appreciated. I don’t want to replace a switch that seems to work if it can be adjusted.

JasonAndreas

Not really and the internal "Cherry" switch is potted/hermetically sealed.

Gregg-K

Seems to me that when my sensor failed a couple of years ago, the internal switch was OK electrically, but its little 1/4" diameter roller (that follows the plastic sensor cam visible in the photo above) had broken up.

I machined up a new roller and fitted it to the original switch, and it has been functioning fine since then.

.. Gregg

Scamper

I had the same problem as Gregg. the small wheel had a flat spot on it and this was causing the light to stay on.
I glued the wheel into place where the wheel was rounded - no more light on the dash!

If you do take this off (and its only a 10 minute job) place a rag under the pulley wheel to prevent any bolts/nuts falling into the void beneath. I didnt and it took me two days trying to fish it out!!!

Its worth having a go as the whole unit is around £70/$150.

Someone may know where to get a replacement microswitch of the right type for a couple of bucks.......

hawk911

I bought a new one from Sunset (no affiliation) for $80 shipped.

f468357

Just to confirm are you saying leave the switch mounted to the car and remove the roller (part that contacts belt)? My car is a '89 and my roller dosn't look like the one in the picture. It looks like it is 2 pieces. The part closest to the engine is plastic and has a flat spot on it where it contacts the belt and then there is another small round steel disc next to that further rearward. My size perspective may be way off but my roller seems a lot smaller than the picture. Thanks.

Gregg-K

I can't picture what you have, but mine comes off the engine as one piece in a plastic housing, and when you take it apart, it looks just like the one in the photo above. The roller you are seeing above is the plastic one that runs against the fan belt.

The switch with its little roller is only visible after you take the plastic housing apart.

.. Gregg

f468357

I finally understand why mine looks different. My roller is gone. Must have broken off. All I have is the little steel bushing that is inside the roller in the above picture. I assume my only option to keep this functional is to replace the switch assembly. The roller isn't servicable is it?

Gregg-K

Correct, replacement is your only feasible option at this point. Sounds like Sunset will be your least cost solution.

.. Gregg

hawk911

Got mine last night, as they were out of stock at Sunset. They mentioned seeing more of these being replaced; had something like 5 in the last few weeks. They normally keep 1 in stock at all times.

Gregg-K

Makes sense: the bit that breaks is mechanical, and it is governed by the universal physics of wear-out.

.. Gregg

hawk911

is that right after Newton's law of gravity?