I don't know if it's the oddly cold weather or rain or what, but I go out to my car this morning, turn on my wipers and nothing happened. I thought maybe the assembly had frozen (although there was no ice--just nearly freezing rain), so I pulled slightly on a wiper arm with them switched on, but they didn't even try to budge. Then, out of nowhere, they came on like I had just switched them on "hi". My fan motor also kicked on--and then everything kicked off again (wipers and blower).

I drove the car to work later, and nothing turned on at all the whole trip. Drove back home from work, and then everything "magically" starts working again--except I could tell that the wipers/blower wanted to kick off briefly at random times.

I'd be surprised if both the blower motor and wipers were on the same fuse--but, even still, this is sporatic behavior and thus I'm not convinced it's a fuse at all. It's definitely not a mechanical issue, as the wipers move freely when they "wake up". And, the blower motor and wipers definitely turn on/off at the same random time.

If it would be a fuse, which should I check? Any other ideas?

 

did you notice if there was anything else not working?
it could be a bad connection in the harness some where.
check the plug on the ignition switch for signs of overheating, if any of the terminals at the switch have been overheated, you'll need to replace them & the switch.
if everything checks good you may have a bad ignition switch.


this may help, open it in windows picture & fax viewer so you can zoom in to read it, you may need to save it to your computer to do it.

 

Thanks for the schematic! I can't look at it right now but I've printed so I can look at it later; the answer is probably somewhere in that.

The only other thing that I found didn't come "on" was the A/C clutch. I didn't do a thorough check of this, but I noticed that when I switched between A/C and anything else on the A/C/heat control, I didn't hear the compressor click on (it's usually pretty obvious when it does). This might be directly related to why the blower didn't come on. Other than those things, everything else I checked seemed to be working fine: power windows, locks, lighting (internal and exterior)... So it seems like whatever "wire" is common to the A/C clutch, blower, and wiper motor.

 

Figured out what the problem was: bad electrical ground.

I relocated my ground strap from the passenger-side head to the drivers-side head--and then fastened the other end onto one of the wiper motor bolts. Apparently that only works for a little while.

I would have thought that more electronic components would go out with a bad ground...

 

Okay I just repositioned my engine-block-to-ground strap: it's still bolted onto the driver's side head, but the other end is now fastened onto a new hole on the firewall that I just drilled (i.e. just like stock, just on the other side). The wipers and blower still do not come on.

However, I noticed that when I rub the ground strap against the casing of the wiper motor or the wiper motor bracket, both the wipers and blower come on again (the wipers are only on when they're set to be on, of course). Is there some kind of ground strap or cable that needs to go from the wiper motor to the chassis?

In the meantime, I really need heat, so I've just taken a universal RadioShack jumper cable (~18-20 ga wire) from the ground strap to the wiper motor bracket. The wire gets warm when the wipers are on, but it seems to be fine as long as I just have the blower motor on.

 

you have a ground problem some where, have you recently done any work to your motor? if so then check around where you were working.

it looks like both systems share the same ground points, G112 & G117. it may be the ground points or a bad splice in the wiring somewhere. i show G112 to be the rear of the left head, G117 location isn't showing up, so it may be misnumbered, it may possibly be G118, which is on the rear of the right head.
if neither of those 2 fix it & the wiring checks good, PM Trickster & see if he has the location for G117.

 

Nope, haven't done any motor work since the rebuild a few years ago. Everything had been pretty much untouched in the engine bay before this electrical "gremlin"--the only thing that changed was the temperature outside (dropped from 60degF to below freezing in a matter of hours and I notice this the first time I start it in freezing temps).

Truthfully, the fact that the ground strap grounded the wiper motor casing/bracket in the past was pure luck. Since the wiper motor has vibration-dampening rubber inserts between the bolts and the case, bolting the ground strap to those bolts only grounded whatever the bolts were fastened to on the other end--but the actual bracket assembly remained insulated from that ground by the inserts. The only reason that had been working was because the ground strap rubbed against the case on its way over there. Nonetheless, everything did work just fine when I had grounded the motor bracket "by accident".

I can always find a more deliberate means to ground that assembly to the new grounding point on the firewall, but I'm wondering why it isn't grounding to the frame in the first place.

You'll have to forgive me but I'm not sure where to figure out what ground points are what (i.e. G112 & G117). What I can tell you is that, when I relocated the ground strap to the driver's side head, I still bolted everything else back to the passenger's side head. Perhaps I need to check behind the passenger's side head somehow?