First time post... Wondering if anyone has had a problem with block heaters and GP operation... Just bought an 80 300td that has been kind of riddled with strange problems. Bought cheap because the previous owner was tired of gremlins. Also wanted to post pin assignments for this vehicle's GP relay as I wasn't able to find them when I was searching.

A week ago no start on the MB. Checked continuity with a mutimeter and noticed that I had two plugs out. It seems from other people that this would still allow me to fire this puppy up, but alas there was nothing.GP light would come on and then I'd wait for 30 sec, crank and crank and crank for one or two minutes but nothing. After cranking the GP light would blink. Figured that was a hint for a newbie so I went online and checked around and found this awesome forum that had tons and tons of info. A month ago I had a mechanic go over the vehicle to get it running and timed etc and he replaced one GP.

So today I pulled the four non-new GPs and tested them with the battery test. Two were completely toast, two were decent but I replaced one of them any for good measure. Why not both? Because I'm broke and $12 is a lot for me.

I also pulled out the wiring harness as I heard a crack when trying to pull plugs without taking the fuel rail off. I wanted to test it an make sure everything was good. In the process I accidentally yanked off one of the block heater connectors. It went into the pit of despair. It's not even magnetic so I can't use the handy picker-uper that I bought because I heard of this horrible pit.

The crack was just the plastic wire casing and all the connections were good. Figure, ok. Time to reassemble. I electrical taped off the broken block heater connection and put everything back together. Not too stressed about the block heater because I live in Portland, OR and it rarely gets below 30 here. Figure half a heater would be fine.

So I get everything back together today standing out in the rain, turn the key and no GP light. Not even flashing. Somehow it seems that I made the problem worse. I just read about the relay click and that sounds good Clicks about 40 sec after I get the key turned. I haven't pumped the fuel system and I'm hoping that plus a jump and I'll be good. just a little nervous about the GP light going out and I was wondering if anyone knew if that was somehow connected to the block heater... Any help would be awesome.


Pin connections for a 300td GP system with block heater:

Cyl1-> X X <-Cyl 2
NoPin - X <-Cyl 3
Block Hea1 X X <-Cyl 4
Block Hea2 X X <-Cyl 5