Vent micro limit switch problem

[Skamper1]

Tried this in another area and got no response so am reposting my question here.
Resealed outside exhaust vent. First the fan worked, then didn't, then did and now doesn't. Think the problem is the micro limit switch. Can I disconnect one of the two wires and touch it to the other wire to see if this is the problem? Can hear it click when lever is depressed. Thanks. Jack

[jdalrymple]

Yes, you can short the wires together and see of the fan comes on. I have seen micro switches at well stocked Radio Shacks. They may have the one you need. They can click and not work. The contacts inside arc and covered in carbon over time.

[Tom Nugler]

No problem touching the wires together.
I had intermittent switches in the TW and replaced them. They acted like yours do.
Replacement is easy. Getting the adjustment right was tricky on the roof vents.

Good luck,
Tom.

[Skamper1]

Thanks for the quick replies. Undid one wire and touched the other. Nothing happened. Will get out the voltmeter and see if there is power coming through. Will be mad at my self if it is just a fuse! Started to rain and will have to wait until tomorrow. What readings should I get on the wires going to the micro switch? Thanks.

[Tom Nugler]

Just checked my wiring diagrams to confirm my recollection at seeing sparks.
All the switches in my ‘72 are wired in on the hot side. My diagram shows the fan and lights at the roof vents and range hood feed off the fuse panel by the converter.
Theoretically if you’ve got lights you should have power at the switch. Practically after 30 plus years any number of connections could be bad. Don’t forget that even if you have 12 volts static on a switch, you could have a voltage drop or bad ground anywhere in the circuit once the load is applied.
Good luck,
Tom

[Skamper1]

Will do some more investigation today. Noticed that there is a bundle of wires under the filter. Have two 3-way switches that are supposed to control the galley lights. Will take pictures of current switches and wires. Am at a total loss when it comes to electricity. Maybe this stems from my sister getting me to stick a knitting needle into a socket when I was 5! Even a 12 volt potential shock still scares me. Thanks for all your advice.

[Skamper1]

Yay! Found the problem. One of the wires from switch to fan motor had a faulty connection. Stripped wires and used wire nut to connect. The fan and switch both work. Now if I can only figure out how the 3-way switches work. Thanks for all the help and advice. Noticed some other wires were connected with oversized wire nuts and then taped to keep them secure. Pulled on each wire and have found two that easily separated. Used proper size wire nut and they are now secure. Did final adjustment to micro limit switch for opening the vent and all works great. Now to eat some beans to check it out!