Since I've owned my Disco the rear window wiper has been stopping in random places when switched on. It works, just does not make a full back-and-forth sweep. Now this week my front wipers are doing the same thing in both intermittent and normal mode. They travel about 1/4 the way up, stop, then after a few moments I can hear the relay in the fuse box click and then they go another 1/2 of the way, then stop, etc., etc.

I already cleaned my wiper switch thoroughly and re-lubed the contacts, so I don't think it's the switch. Anyone know WTF is going on?

 

 

Thanks, I believe you are correct. Can't find reference for part numbers for either the front or rear park switch. AB says they don't sell switches, only new wiper motors which either come with park switches installed or have them built-in. Another project.

 

If the above doesn't fix it, pop off the cowl and check to see if the wiper transmission assembly is secure. When I bought my truck, it had a habit of stopping halfway through the wipe, then complete the wipe a short while later. Pretty dangerous here in the PacNW. Come to find that the assembly was loose and would bind from movement.

 

 

I'm going to look at it tomorrow as I'm taking a break from wrenching, plus it's 9/11 and I'm feeling a bit down. Anyway, it's been the rainiest July, August and start to September I can remember here in Pennsylvania. We usually get a break from cutting the grass every week during Summer but not this year - it's like a tropical rain forest out there.

I know the transmission assembly is not binding so either the internals are screwed or it's something else unknown. The front motor assembly has a ground strap running to a stud in the cowl area so I'm going to check that first to see if the ground is bad; that could definitely be the culprit, at least on the front wipers.

 

 

Everything is repaired. I have access to a junk DII so I just replaced the front and rear wiper motors since the spares are known to be 100%. My transmission assembly was fine but front ground strap to the motor was badly corroded. I suspect this was a contributor to the erratic behavior, so try cleaning the ends of your ground strap first before swapping the front motor.

The rear motor must have had worn internals because the replacement is working perfectly.

These things have rivets holding them together which could be drilled out to open up for inspection but I'm short on time this week.

 

 

You can reach the front ground strap without taking the plenum apart, just use a step stool to get closer to the center of the vehicle. Two 10mm fasteners, nut on the stud and bolt on the motor assembly. Good luck.