Weird electrical issue...

...with my wipers and fan. Not the engine's fan, but the fan for the cabin air.

I took a long trip in my 90A from Vancouver to Edmonton and then home again (I'm actually writing this from my last stop in the Okanagan) with my GF.

And somewhere along the line in Banff/Jasper national parks, my wipers would stop working at the same time (as I soon discovered) as the fan for the internal ventilation system would fail. But then they would start working again; almost always (but not 100%) correlated with stopping and then restarting the engine.

Now, check me on this: according to the manual, the wiper and the ventilation fan are on different circuits, right?

So does anyone know where I should start looking for the fault? Because I don't get it.

Reply to
Alan Baker
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No idea about your problem -- long-distance troubleshooting of electrical problems is difficult at best. (loose connection comes to mind though)

But while you are there make, sure to get some of the local wine which might help you forget the problem... ;-)

Reply to
John McGaw

I am not familiar with this particular electrical system, but problems described as "weird" are usually related to bad grounds. Separate circuits (ie, separate fuses, separate switches, etc) often rely on one good path to ground for the return of the circuit. If that ground is bad due to corrosion of a loose ground strap, all sorts of strange things can happen. Usually things like having the turn signals stop whenever the brakes are applied etc happen, but it is possible your symptom is caused by a loose ground somewhere.

Reply to
greenpjs

For the NB (not sure about NA, but probably the same) the electrical diagram shows that the air-con blower fan / rear defogger(if fitted), wipers, and electric windows (if fitted) share a common circuit from the main ignition switch (black/red striped wire from ignition switch on NB) before the fusebox. I'd be starting a search there - especially as you've observed that it's intermittent depending on stopping and restarting. Likely to be either a dead ignition switch, or trace the appropriate wire from ignition switch back though to fusebox for loose connection / damaged wire.

Reply to
Me

Clarifying the wire colour from the ignition switch to the interior fusebox, it should or could be black with a red stripe - not the one that's red with a black stripe.

Reply to
Me

I agree. There are annotated photos at miata.net identifying the underhood ground points. They vary somewhat by year; I don't know if Canadian Miatas differ from U.S. models, but the pictures should get you started, anyway. Disassemble and clean each contact surface until shiny with emery cloth or a typewriter eraser (can you still buy those?).

Reply to
Lanny Chambers

Except this problem isn't weird, as the circuit for wipers and heater/ac fan is shared at the ignition switch, as per my other posts.

Reply to
Me

I've had very good luck using 800-1000 grit sandpaper for cleaning up ring connectors, and you can polish up a male spade with that as well. It's less harsh that emery cloth in my opinion, that tends to remove a bit too much material for my liking.

Which makes me wonder if the OP could jiggle the ignition key next time this happens..and if that rectifies the issue right away I'd go for a new ignition switch. And I wouldn't put it off either, as this could be a fire hazard if that circuit has high resistance due to a worn wiper in the moving parts of the ignition switch.

Chris

Reply to
Hal

We drove a 72 VW bus from LA to Quebec to Key West and back to LA. It had a dodgy ignition switch - often needing a wiggle to get it to work. Detoured through Death Valley on the way back - where in the middle of nowhere, suddenly masses of smoke, sparks, and heat erupted out of the steering column, and the bus stopped dead. A local cop stopped to check if we were okay while I was working on it - sorting out a mass of melted burned plastic. We had plenty of water and food with us, and he offered to come back to check at regular intervals on his beat. I don't think in that case it was the switch itself that overheated/shorted out, but the constant wiggling and loosening contacts at the back of the switch resulted in a short - perhaps eventually wearing through insulation. A bit hard to tell from post mortem.

I'm not sure if general longevity of contacts in the ignition switch might be related to whether there's a load on the circuit when you switch it on and off, so that repeated slight arcing wears down the contacts. I try to remember to switch fans, wipers, radio etc off before I shut it down. My wife doesn't - especially the CD player left LOUD - and that has the beautiful characteristic of a few seconds delay while the disk initialises in the player, then some very nasty shock - sometimes she listens to Rammstein in the car.

Reply to
Me

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