Rear Defogger - PeachParts Mercedes-Benz Forum

BWatson · #1 03-05-2003, 03:22 PM

My rear defogger use to work fine. Now when I turn it on, shuts off automatically after a few seconds. Anyone have a clue?

rickg · #2 03-05-2003, 04:30 PM

You actually need it in LA?

Sorry. You didn't need that.
Not sure, but I think these have a timer of some sort. Mine will turn itself off after 5 min or so. May be the timer is on the fritz.

Wasuchi · #3 03-05-2003, 07:26 PM

If it makes you feel any better mine shorts out and makes static on the radio, only 3-4 "wires" work. Luckily I hardly ever need it because I'm not replacing the rear window until it breaks.

jbaj007 · #4 03-05-2003, 10:03 PM

Rear defogger timer relay in the fuse box.

Fisherman · #5 03-06-2003, 08:14 AM

I have one wire still working and it would be nice to have a few more if possible. I seem to remembe some kind of stuff that you could apply froma tube and it supposedly made the electrical connection agan but thought I'd ask here first.

Erikir · #6 03-06-2003, 09:03 AM

You're lucky, with one wire working. I just have 2 small spots on one wire that defrost :p This is not a good thing in a place as damp as Vancouver.

PaulG · #7 03-06-2003, 09:25 AM

Yes, you can repair these heating "wires" with silver-loaded paint. Normally available at Radio Shack (does Radio Shack still exist?)

It's very difficult to make a neat job of it though.

If I was trying it again, I would try painting the stuff on between 2 strips of masking tape.

Fisherman · #8 03-07-2003, 10:57 AM

Thanks

#9 03-07-2003, 05:51 PM

Is there not a "overload system" as well, at least on the 201's I thought if you had a heavy electrical load, it would load shed the defogger. With the nasty PDA manual I have, maybe I am confused with another subsystem!

Cheers, Mack

mpnye · #10 03-08-2003, 03:09 AM

Look for a HAIR LINE CRACK on the FUSE . . .

jjalex · #11 03-08-2003, 11:07 PM

When you repair the wires with the silver loaded paint from Radio Shack, do you paint the entire wire or do you look for a crack in the wire and repair it?

I just don't understand why they stop working, but I have about 5 dead ones in the worst place and it snowed againt today...

Thanks

Fisherman · #12 03-09-2003, 09:54 AM

MPNYE,
Are you saying that a hairline crack on a fuse will allow one wire (same one) on my rear defrogger to work but none of the others?

Sorry but I don't get how this could effect my defogger...

jjalex · #13 03-09-2003, 11:39 AM

Fisherman,

I think mpnye is referring to the original question of the defogger turning off after a few seconds...

mpnye · #14 03-09-2003, 12:37 PM

The fuses sometime get a HAIRLINE CRACK which is BARELY VISIBLE to the naked eye . . .

When you turn the WS HEATER on, the HIGH current flow heats the fuse and EXPANDS the crack OPEN after a short period of time, cutting power to the HEATER. Then after a while, when the fuse COOLS and CONTRACTS, the connection is RESTORED and it works for a period once again . . .

YES . . . my post refers to BWATSON

jjalex · #15 03-09-2003, 05:24 PM

Does anybody have another suggestion for finding the silver loaded paint?

I went to Radio Shack but they didn't have any.

Thanks