PeachParts Mercedes-Benz Forum - View Single Post - 603 pre-glow time delay relay dead again

swogee · #3 08-09-2006, 03:22 PM

I don't think there is any easy way of using a switch to bypass the time delay relay for the glow plugs. The glow plugs initially draw up to 80 amps during preglow and that tapers down as the glow plugs warm up. The actual glow plug relay on my 1987 300TDT is located on the drivers side fender and is a rectangular block mounted to the fender sheet metal. The G.P. relay varies the time delay before it shuts off the GP lamp in the instrument panel based upon the temperature of a sensor in the relay body. After the GP lamp shuts off, power is still applied to the glow plugs to for a total (including the GP lamp time) of roughly 35 seconds.

If the GP lamp is not lighting there can be multiple causes. Do a search for glow plug lamp and a bunch of stuff will come up.

As for running rough after startup due to no glow plugs, I don't think it will hurt anything in the long run other than harder starting and more smoke.

-Steve