1997 Sharan glow plug relay - where?

[the_old_diver]

Is it Relay 103 on the panel near the fuses below the dashboard, or is there another bigger one somewhere else? I read somewhere that the plugs draw about 9 Amps each and 103 doesn't seem big enough to handle 36 Amps - that's welding current :-)

Interested because 103 seems to be functioning OK yet the glow plug symbol on the instrument panel goes out after about 1 second, and the car won't start...

Cheers, OD

[kenney]

Hi Yes you are on the right track 103 is the glow plug relay in position 12 on the relay plate,have a look too at the glow plug fuse 60amp at the top of the relay plate.If this is OK then you need to check the current at the plugs,if you have current at the plugs,then its probably the plugs

[the_old_diver]

Hi kenney,
Thanks for the reply. I have tested relay 103 today by applying 12v across the coil terminals and measuring the resistance across the contact terminals - which is 0.0 ohms when energised - so the relay seems OK. I checked the 60 amp fuse and that was OK too. I even stuck a piece of iron wire into the contact terminal holes on the relay board, and it burned my fingers nicely, so there's voltage around. However, the plugs don't seem to get warm and the car still won't start. The (rather thin for 40 amps) wire from the glow plugs seems to go into a circular black plastic connector at the r/h end of the engine block, but I can't trace it beyond that point.

The glow plugs themselves are brand new. I did try to measure the voltage at the plugs but wasn't sure I was getting a good reading. I removed the connectors from the plugs and stuck a multimeter probe into one, and grounded the other probe, then went inside and switched on the ignition, and through the windscreen saw only 0.4 volts on the meter when the glowplug light was on on the instrument panel, dropping to 0 when turned off.

Hmmm. "Summats up", as they say in Lincolnshire.

In another thread I mentioned that I was replacing the Relay 109. Under a stereo microscope I could see a number of dry joint on the pcb, but even after resoldering them it still wouldn't conduct when energised. What's worse, even with a new 109 installed, it still won't start :-(

Any ideas, anyone?

[kenney]

OK What you can do now is remove the rele and bridge contacts 4 and 6 on the relay plate,(mind your fingers)you now eliminate the relay the ignition switch and the ECU,you should now have 12v at the glow plugs.Try this and we can take from there next step.

[the_old_diver]

Thanks for that, kenney. Garage is closed 'till Monday but I'll try it then.

The car probably has more than one thing wrong with it, so I can spend some time now figuring out what else might be wrong, causing the engine to fire for a couple of revs and then die, three times in a row, followed by nothing till it's had a rest. I read somewhere ( been to hundreds of pages!) that if the ecu doesn't get an input from the crankshaft AND camshaft sensors within one second it thinks it isn't going round and then shuts the fuel off, just to be on the safe side. Now I need to find those sensors... happy days!
Cheers, OD

PS Man at garage where it is lying said yesterday he'd tried applying 12v direct to the (brand new) fuel shut-off valve a few months ago - wonder if that has caused a problem? Off to try to find a 1997 Sharan 1.9 TDI CL relay layout diagram. (Crasher - if you read this - I haven't forgotten your advice that it is an immobilser issue - it's just that I can't get it to the main dealers without a whole lot more delay, and considerable expense, so I'm looking for possible alternative causes in the meantime )

[the_old_diver]

OK What you can do now is remove the rele and bridge contacts 4 and 6 on the relay plate,(mind your fingers)you now eliminate the relay the ignition switch and the ECU,you should now have 12v at the glow plugs.Try this and we can take from there next step.

Right kenney! In order to keep the plug relay energised long enough to get a reading at the plugs I had to remove the G62 water temp sensor. Voltage is about 12v when no plugs are in circuit. I measured their resistance with a digital meter two were about 1.7 / 1.8 ohms, two were around 0.8 / 0.9 ohms.

I bridged terminals 4 and 6 on the glow plug relay socket with a short loop of monel seizing wire held with a pair of pilers. Just as well- it lit up to a nice orange colour. Checked fuse afterwards - still OK. Engine still won't start and Todays codes are:
"0522" - G62 disconnected, because I did that,
"0542 05-10" - one I haven't seen before, apparently meaning "wire to ignition module". Unfortunately the code list I have isn't very good at completing sentences...
"01237" - referring to Fuel cut-off valve solenoid valve. I did disconnect it today and with the ignition switch on I stroked the solenoid contact with the disconnected wire and it clicked at each contact, so I'm guessing that this is what caused that code.

So I'm left with a possibly genuine 0542 code and the glow plug data mentioned above.

Over to you, kenney :-) Or anyone else...

Cheers, OD

[kenney]

I assume the battery and starter is cranking the engine fast enough?, fault code 0542 is the 3rd injector which contains the needle lift sensor,check the wiring to it and the resistance should be 80-120ohm.Have you tryed loosening the injector pipes to see if there is fuel coming to the injectors?