My mechanic is stumped. Glow plugs keep coming back on. - PeachParts Mercedes-Benz Forum

muleears · #1 07-08-2010, 07:19 AM

My 98 E300. We replaced the glow plugs and fixed another problem the car had but now the glow plugs come back on after the car has been running a minute or so, and they don't go off. We replaced the part (I forget the name of it) that controls the glow plugs. Turns out it was a reman. unit that had failed but the gp's still come back on. Any ideas?

tangofox007 · #2 07-08-2010, 08:06 AM

I would suspect a loose/intermittent electrical connection that is causing the same condition as turning the ignition switch off and back on, thereby "recycling" the glow plug timer.

vstech · #3 07-08-2010, 08:53 AM

how long are they staying on? the newer controllers are designed to provide an afterglow with the plugs, but shouldn't come on more than 3 minutes or so...

muleears · #4 07-08-2010, 09:21 AM

They don't go off until you turn the car off.

connerm · #5 07-08-2010, 10:53 AM

I suspect the wiring harness is compromised somewhere. Mine (95 E300D) was at 110,000 miles way back in 2003.

muleears · #6 07-08-2010, 10:59 AM

Quote:

Originally Posted by connerm

I suspect the wiring harness is compromised somewhere. Mine (95 E300D) was at 110,000 miles way back in 2003.

Did you have the same problem as me?

whunter · #7 07-08-2010, 12:23 PM

Quote:

Originally Posted by connerm

I suspect the wiring harness is compromised somewhere. Mine (95 E300D) was at 110,000 miles way back in 2003.

A bad ignition switch or failed wire harness.
Most 1991-1995 are known to have the biodegradable wire harness.

Wiring Harness issue; ALL
http://www.peachparts.com/shopforum/showthread.php?t=166883

..

muleears · #8 07-08-2010, 12:45 PM

[QUOTE=whunter;2501372]A bad ignition switch or failed wire harness.
Most 1991-1995 are known to have the biodegradable wire harness.

Thanks for the help.

This is on my 98, I didn't think they had the biodegradeable harness?

whunter · #9 07-08-2010, 12:53 PM

[QUOTE=muleears;2501384]

Quote:

Originally Posted by whunter

A bad ignition switch or failed wire harness.
Most 1991-1995 are known to have the biodegradable wire harness.

Thanks for the help.

This is on my 98, I didn't think they had the biodegradable harness?

Pinch, abrasion, cutting and/or water intrusion can cause the same symptoms.

muleears · #10 07-08-2010, 05:02 PM

Can I just wire the GP's to a switch I control, so I can turn them on and off? Or would that be suicide?

Bob Albrecht · #11 07-09-2010, 04:40 PM

This happened to me. I checked all of the glow plugs at the control unit, cleaned the connectors, and it went away. I think cleaning the connectors or jostling the control unit did the trick.

muleears · #12 07-15-2010, 08:15 PM

Sorry for the long delay, been away from computers on a little vacation. Came home to find out that the GP controller we got to replace the bad one was also bad. So now we're waiting for another replacement GP controller. This MUST be the problem. Wish me luck...

glenlloyd · #13 07-15-2010, 11:14 PM

Quote:

Originally Posted by whunter

A bad ignition switch or failed wire harness.
Most 1991-1995 are known to have the biodegradable wire harness.

Wiring Harness issue; ALL
http://www.peachparts.com/shopforum/showthread.php?t=166883
..

That was my first thought, ignition switch failure.

steve a

vstech · #14 07-16-2010, 07:04 AM

Quote:

Originally Posted by muleears

Sorry for the long delay, been away from computers on a little vacation. Came home to find out that the GP controller we got to replace the bad one was also bad. So now we're waiting for another replacement GP controller. This MUST be the problem. Wish me luck...

why do users ask for help, receive help, then do what they want to do?

Brian Carlton · #15 07-18-2010, 01:42 PM

Quote:

Originally Posted by vstech

why do users ask for help, receive help, then do what they want to do?

Happens time and again. I believe folks already have a preconceived idea of their issue and are simply hoping for confirmation from one member. If they get that confirmation, they proceed with their preconception. If they don't, sometimes they still continue with their preconception.

Shoulder onward.........it's not personal.