92 300D wiper blowing fuse at low speed
 

I just recently bought a pristine 1992 300D (only 211k miles!) and one week into our honeymoon the wipers stopped working. I have searched all the threads I can find on this site, (I'm a newby to the Benz forum) but could not find anything specific to my model year. I removed and replaced the wiper motor ($200 ouch) thinking it was bad but it was not. The fuse blows only when the wiper control is set to position I (intermitent), everything works fine in positions II and III. Before I go out and spend more money on parts I don't need, does anyone have any suggestions as to what could be causing the fuse to blow at low speeds? Is there a wiper relay that could be bad? If so which one and where is it? Could the wiper control stalk be shorted? Any help will be greatly appreciated.

Thanks,

ASantoni
92 300D (211K miles)
05 Frontier (20k miles)

I'm not familiar with the wiper system but in looking at the Factory Service Manual looks like there is a combo relay (in the box behind the fuses), but I'm putting my money on the wiper switch itself being bad.

The relay you want to look at is at position 'H', which is in the front center of the relay box (front meaning closest to front of car). It's the biggest one in there. You can only see the 'H' once you pull the relay, as it is printed under it.

It also serves to control your turn signals, hazards and rear window defroster. Are you having problems with those too?

Oh you should add to your sig that the 300D you have is a 2.5 Turbo.

Justin,

Thank you for posting a response so quickly. I'm afraid too that it may be the switch itself which I am not looking forward to replacing. Just to make sure, I want to pull the relay out and activate the switch to see if it still blows the fuse. Right now with the wiper motor completely removed, it will still pop the fuse when wiper switch turned on to position I.
I am not having problems with the turn signals, hazards and rear window defroster although I just replaced the headlight switch a couple of days ago for an unrelated problem (15 years old wore out).

Thanks,

ASantoni
92 300D 2.5 Turbo (211K miles)
05 Frontier (21k miles)

That would be a good test.

The wiring for the wiper goes through the fuse, to the switch, to the relay, then to the motor.

Congrats on your 92. I bought mine with 176 thousand in 2005 and I am going to roll over 200K in Febuary. There is a good community of 124 2.5s here. Not as big as the 123 and 126 but we are here. I have not seen this problem but I would bet on the switch as well. My mulit switch on my Grand Am has been screwing up for while.

If it is the switch and you can find the wires and isolate the switch. You should be able to test the resistance with a mulitmeter. If it goes to zero you have found the problem.

It's the switch
 

All,

Final determination is that the problem is with the switch. I did not want to mess with the steering wheel removal so I took it to a local shop here in Orlando to have it replaced as well as do a compression and injection pump check while at it. Thank you for the posts.