Glow Plug Lights Always On - Page 2 - PeachParts Mercedes-Benz Forum

tangofox007 · #16 01-17-2010, 12:51 PM

Quote:

Originally Posted by Oracle12345

check your ground gonnection

What's your theory on how a bad ground could cause the GP light to remain illuminated at all times?

tangofox007 · #17 01-17-2010, 01:18 PM

Quote:

Originally Posted by JimSmith

The charging light being on suggests the voltage regulator assembly with the brushes is bad. Especially if it is barely one and goes off now and then, kind of as the engine speed picks up. Brushes wear out and then only intermittently make contact - adds resistance to the circuit and you don't have the juice needed to run the car off the alternator. Thus, the dash "charging" light comes on.

This is likely a separate problem from the one that has your glow plugs energized all the time.

If the glow plug cycle has been significantly extended, it is possible that the alternator problem is a consequence of the GP problem.

Quote:

Originally Posted by JimSmith

I would think the fuse would melt under those conditions though.

Jim

Why?

my123ca · #18 01-17-2010, 07:56 PM

Quote:

Originally Posted by tangofox007

What's your theory on how a bad ground could cause the GP light to remain illuminated at all times?

The temperature sensor is connected directly to ground. If there is no ground, the temp sensor wont work and therefore wont tell the timer to turn off?

Hella GP Relay any good?

tangofox007 · #19 01-17-2010, 09:27 PM

Quote:

Originally Posted by my123ca

The temperature sensor is connected directly to ground. If there is no ground, the temp sensor wont work and therefore wont tell the timer to turn off?

The temp sensor is grounded through the same circuit as the solid state device that controls the relay. If that ground is bad, the timer isn't going to work in the first place. Neither is the light.