Glow plug light not illuminating on '87 300TDT...
 

Just went out for a drive and noticed my glow plug light is not illuminating...

Car seemed to start fine however after waiting about the "normal" 10 to 15 second pre-glow time before engaging the starter. Tried swapping out the light bulb with two other bulbs I know DO work but neither would light when in the glow plug socket.

Any ideas on relays or other things I can check?

J.G.

If everything is working as it should (would you be posting if everything were working? :) ), no glow light means #1 glow plug is bad or at least two others are bad. Pull the 6-pin connector at the glow relay and check resistance at each pin. Should be about 0.7 ohms. An open circuit or higher resistance indicates a bad glow plug. There are microscopic numbers by each contact identifying which cylinder that wires leads to.

Sixto
87 300D

Thanks...I have been pretty sure one plug has been bad (or going) for a while...a little rough on initial startup with white smoke that clears up within two to three minutes after warming up, but until today, the light still actually worked.

Where is the glow relay??...I'm by nature a W123 diesel guy, so I'm a virgin with W124 problems! :icon_redface:

J.G.

About the same place as a W123. Aft of the ABS pump. You can't pull the cover straight off. Pull off the upper edge, pivot it down about the lower edge then slide it towards the engine.

Sixto
87 300D

Many thanks! I'll give it a shot.

J.G.