Just installed a new water pump in my 81 240D to fix the coolant leak.

Every now and then when I go to start my 240D the glow plug dashboard light won't light up and if I wait the 30 seconds the car is very hard to start. I'm thinking that the relay isn't working, but I'm not sure, could also be bad glow plugs?

I see that there are two relays in a box in the engine area that have part#001-542-0219, what are these?

Thanks,

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1981 240D
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