Yesterday morning my Mitsubishi WP-255Q3 water pump stopped.

At first I thought that it was low voltage causing the thermal switch to activate but the voltage was 217vac. I then bypassed the pressure switch and the pump started. Conclusion, a bad switch. I removed the cover from the switch and hundreds of ants swarmed out. I then used an air gun to clean the switch and globs of dead ants came out, but the pump still would not start. I thoroughly drenched the contacts with contact cleaner and let it sit while I went into my workshop to look for a new switch hoping that the one that I had had the correct size connector on it. I dried out the switch again with air and plugged it in and the pump started and is still working.

I've had problems with ants in switches in appliances that are used to cook food, but these ants were truly suicidal as there was no food within 20 meters.

Yup, those teeny-weeny little chaps like electrical stuff. They get in between the switch contacts, eventually enough get squashed that the switch fails. Crushed ant is remarkably difficult to remove from contacts without dismembering the switch. All switches contain at least one "ping fxxk it" (an engineering term for a small spring, it goes "ping" you say "fxxk it").

I've put ant killer in the water pump switch which seems to have stopped them, same in the downstairs light switches and the (supposedly sealed but they still get in) outdoor lights.

Had the same problem with our Mitsubishi pump just a few months after installation. Went to the local pump shop and they sold me a replacement (made by Four Star if I recall) that had contacts about double the area of the original part. No problems for four years after that.

Yup, those teeny-weeny little chaps like electrical stuff. They get in between the switch contacts, eventually enough get squashed that the switch fails. Crushed ant is remarkably difficult to remove from contacts without dismembering the switch. All switches contain at least one "ping fxxk it" (an engineering term for a small spring, it goes "ping" you say "fxxk it").

I've put ant killer in the water pump switch which seems to have stopped them, same in the downstairs light switches and the (supposedly sealed but they still get in) outdoor lights.

I've been having that problem for years when trying to repair switches.

Didn't realize there was an official engineering term for it

Is it a tip: fill some ant killer (granulate, powder) in the pump housing?

It's not food they're after - they used to go in my internet router until the pest people came round. I think it's to do with warmth or electrical signals or something - I did read an article on it a while back.

Slightly changing the topic which I believe has been on another forum,but anyway.

Small flying insects like mini bees, which like to make gooey nests in small holes, and if disturbed swarm and give minor bites more than stings. I have had these nesting in the ends of the revolving poles of my retractable blinds. Have sprayed the with many insecticides to no avail. This week I unrolled the blind and observed repeating holes as I unrolled it. Something had eaten into the blind right through to the roller. So making a repeating pattern which when unrolled looks like lace curtains. My first thought was it must be a rat, or squirrels which abound in my garden. But when I unrolled the blind completely, the bees/flies whatever had produced their sticky goo along the length of the rollers recess, the same length as the eaten pattern in the blind. Question. Could it be the bees/flies eating their way out, or rats/squirrels eating their way in? Do these ants eat blind material? Any one with experience and advice on this. Sorry it has been so long winded.

Spray WD40 on the Cover before you close it. Ants hate that stuff. If you don't believe me spray some in an Ant Hill and see what happens.

will wd40 keep the ants from coming in the house if I spray it on the outside walls?

You have heard the phrase " There's a bug in my computer" yes?. Well, the phrase originates from a cockroach that was trapped between the relay contacts of a computer in the 1950's. It is a fairly well known fact that insects are attracted to electrical equipment, much to their demise. Snakes, however, seem to like high voltage power supplies ( so double check whether those cables, really are cables)

Yeah, sometimes they just decide to make a nest some-place and if that happens to be inside some electrical device it can be problems.

They did an external wall fan at my place recently, like your experience except including bug spray, I got it working after cleaning.

Fortunately not the red (fire) ants.

I saw a buried conduit run where ants had completely stripped the insulation off the wires. It was at a friends desert property were everything was de-energized when they weren't there. We were powering things on and one breaker tripped as soon as we flipped it on. Pulled the cover and found the trail of ants coming out of that conduit.

Have heard that rats think some of the plastic insulation tastes sweet, so they chew on them. We figured the same held true for the ants.