Glow plug circuit

I think I have found my starting problem its the glow plugs.

I removed them and tested each one and they work perfectly glowing nicely in about 5 seconds.

I then refitted them and put a meter on them and nothing??

Tested the supply wire and its giving only 3.9v for about 8 seconds then switches off as it should and if I connect it to the first glow plug and try again it goes to -00.00v

After searching previous threads I think I found the relay behind the drivers foot panel and that’s clicking as is the timer relay when the ignition is switched on.

Any ideas why I am only getting 3.9v then -00.00v and how to trace the fault.

Find out what the under dash relay is for and why it's clicking. My wiring diagram and no doubt like yours is showing a direct feed via a fusible link to the glow plug timer relay in the engine bay with the relay operating supply from the starter solenoid.

The above is based on a 300 wiring diagram...

Hi Discool yes its a 300tdi

I am trying to work from this diagram, electrics are not my strong point, hammer and welder are my strong ones

horse62 said:

Hi Discool yes its a 300tdi

I am trying to work from this diagram, electrics are not my strong point, hammer and welder are my strong ones

Click to expand...

That's the one M8 as u see no other relay involved.
If u can't find what the other relay is for..let
me know the position ie number in from the door pillar and colour better still a pic and then hopefully from the other books I have I'll be able to tell u what it's for.

Cheers mate I will have another look at it tomorrow

Spent the morning tracing the problem and found a bodged wire that had completely broken in two it was hidden under the fuse box in the engine bay.

Starts on the button now Its not done that for a long time.

Your not wrong there, and well done

Well she starts ok when cold, when hot its like this

Disco - YouTube

It runs like this for a few mins, then clears and drives ok? The smoke stinks of un-burnt diesel, its really doing my head in!!!

Looks like I will have to book it in to a diesel specialist to sort it