2.5 AFB Glow Plug problem - advice needed

[Grant_H]

Hi all,

My engine seems very reluctant to start on these cold mornings, and I've done a little digging:

Leaving the door open slightly so the interior lights come on, engage the ignition and the glow plug light comes on. Up until I hear the relay 'click' for the GPs, there is no change in the brightness of the interior lights, neither is there any movement on the dash battery gauge.

Could this simply be a result of a blown fuse? Or are there any more likely places for a broken circuit?

Many thanks.

Grant

 

[Sulli79]

Can you check the voltage then current at the glow plugs?

 

[aragorn]

Have you ever changed them?

If they're 12+ years old they could just be dead.

 

[Grant_H]

Hi, thanks for the replies. Yes, they were changed last year.

I've checked the ECU box in the engine bay and both 60A fuses are fine. Any other areas?

 

[Grant_H]

BTW; where's the Glow Plug Relay on the 2.5 TDi and what's the number?

 

[desertstorm]

Glow plug relay J52 is in position 4 on the micro-central electrics I assume that is under the dash I think behind where the main relays are located.

Audi A4 Relay Panel Location and diagram commentary - YouTube

This is for an A6 but the glow plug wiring is the same as an A4.

http://www.google.co.uk/url?sa=t&rc...hN1hPsAlszdjEEA&bvm=bv.59026428,d.ZGU&cad=rja

Seems to be the bottom line of relays under the dash.

http://www.csupomona.edu/~bvnorum/cars/c5_fuse_relay.pdf

karl.

 

[desertstorm]

It's marked 202 I think. You can usually tell as they have very thick terminals to carry the current.

AUDI RELAY GENUINE 800 951 253 V23134-J52-X300 | eBay

Karl.

 

[Grant_H]

Thanks; I think I've found the relay it's the blue one number 202 (same as the fuel pump relay I believe).

I was actually watching that youtube vid about an hour an hour ago

I'm now down to finding a wiring fault; any multiplugs / connectors prone to breaking on these cars?

 

[Grant_H]

I think I'll buy a new relay though; just to be sure.

Thing is though; it still clicks to engage. Can this still be defective if you can still heare the 'switch'?

 

[desertstorm]

They can still be faulty if the contacts are burned. You can take the can off the relay to see whats going on inside. Best thing to check though is with a multimeter on the fuses. If you are seeing 12V there then the relay is good and the wiring up to there is good. disconnect the glow plug cap and check there next.
you can check the glow plugs in situ, usually if they are less than 1 ohm they are good.

Karl.

 

[Grant_H]

Thanks; the glow plug fuses being under the ECU cover in the engine bay, presumably?

 

[desertstorm]

yes