Glow plugs not getting any electricity

[alin_999]

Hi guys!

Yesterday I thought I should replace the glow plugs as they seemed to be the problem for the difficult start in cold weather.

After I took them out from the engine and tried them with the ignition on I noticed that none were working, tried the same thing with the replacements same answer. Checked the wires with a multimeter, no voltage. The wires do not look damaged.

Any idea why there is no current coming to the glow plug wires?

[alexperkins]

Glow plugs only work below a certain temperature. They’ll only come on when it’s less than 5C I think

[alin_999]

Ok, decided to take it to service, the guys checked the car, 2 glow plugs dead, need to replace.

The wiring was good it seems just didn't check them the right way.

The mechanic told me I should also replace a certain relay, responsable for the glow plugs. Is it the 109 relay ?

[alexperkins]

109 is the ECU/ECM relay

100 is the glow plug relay

If your 109 relay is original, its worth replacing it also as there is a known fault with these relays.

[alin_999]

I've read that the black version of the 109 relay has issues. My car has the grey one. Are there known issues with this one also?

[alexperkins]

Some of the earlier grey 109s are also faulty

My 2006 1.4 TDI had a grey 109, and that failed making cold starts very difficult.

[alin_999]

Ok, thanks for the tip.

Buying one from ebay would be ok, or should I search for those only at VW official dealers?

[alexperkins]

Needs to be a decent quality one so Febi, Meyle or original

[alin_999]

I purchased the 109 relay from ebay, original product.
Can't seem to find the 100 relay though anywhere on the web

A link would be highly appreciated.

[alexperkins]

Can you buy from eBay UK?

[alin_999]

Yes, I can.

[alexperkins]

https://www.ebay.co.uk/sch/i.html?_from ... 5573.m1684

Febi 34751 also

[alin_999]

The values on the scheme from my relay are: 3 1 2 5.

On ebay, I only see relays with high values 70-80.
Do they also work?
By the way, what do these numbers stand for?

[alexperkins]

Can you send me a photo of your relay? That sounds like pin numbers.

The 70-80 is the amperage the relay is rated for as glowplugs pull alot of current.

Relay 100 is Relay 100

[alin_999]