heater plugs?????????????

[Rustwagen]

Got a Wv t25 1.6 td problem is no live feed to heater plugs when yellow dash light is on, you even hear the relay click but all the time no live feed to the glow plugs the big metal fuse under the relay is fine too i've tried tracing the wire back but it just leads into a tangle of wires under the relay and electrics aren't my forte

[pauly8888]

How do you know there isn't any live feed at the plugs? Have you tested the plug feed cable with a multimeter?

[ewenmaclean]

good question - how have you tested this? Have you checked the 50 amp fusible link in the black box in the engine bay underneath the relay? If this is gone you won't get any power, but it's worth testing the resistance of the circuit before you just resintall to check you don't have a short somewhere...

[Rustwagen]

With a test lamp from the earth to the wire to the plugs whilst the yellow light is on, fuse is fine and you hear the relay click

[ewenmaclean]

Hello,

I think you have keep going backwards in the circuit from the glow plugs until you find a live. The fuse is under the relay - are either of the end points here live? If not, can you take the relay out and test the 30 pin? There should be a thick red wire going to the relay directly from your starter motor if memory serves correctly. Maybe worth looking there -

hope you find the problem

Ewen

[Rustwagen]

Sorry for the late reply - Yes Ewen both screws either side of the fuse link are live, how do i remove and test the relay as it seems to be well stuck also how do i test it once removed? sound to sound thick but electrics just aren't my thing.

[ewenmaclean]

Hello,

there should be pins on the relay labelled "T", "L", 30,50,85,86 and 87

if you give earth and +12V to 85 and 86 then this should make the relay "tick", bridging the pins 30 and 87 which power the plugs. If you have a couple of crimp connectors this is fairly easy - you can, for example, use the feed to the low revs oil pressure switch which isn't far away as a 12V signal (ignition on) - connect this to 86, then connect 85 to any earth on the body or engine block - wrap bare wire around an injector if you're feeling lazy (bad practice I know). Now use your existing test lamp circuit you but connect it "through" pins 30 and 87 - i,e, with those pins on the relay in series with the test lamp cirtcuit. With 86 having power and 85 being earthed, this should make the relay click and give continuity through 87 and 30.

T is temp pin, L is for the glow plug light and 50 is the starter signal - none of these are important for this test.

Hope that helps

Ewen

[Rustwagen]

Thanks Ewen i'll check them all today and let you know

[ewenmaclean]

Hello,

Thanks - would be good to know how you get on. Just as a note - it'd be a good idea to put your location in your profile - there are loads of helpful folk here happy to help out in person. I'm in Edinburgh and would be happy to swap relays etc to rule stuff out, or lend you a multimeter etc...

Good luck with the diagnostics!

Ewen

[Rustwagen]

Will do mate when i figure how to use the whole page lol i'll also put a pic of my van up i'm in Chester on the English side of the North Wales border fyi

[Rustwagen]

Right then Ewen

I did as you said, connected a live feed to 86 pin and earthed 85 pin which gave continuity through 30 pin and 87 pin which i then gave a live feed to 30 pin at the same time which in turn gave live feed to 'L' but not 'T' i also checked for continuity between where 87 pin plugs into the relay housing, and the wire to the glow plugs and again there was continuity there threw it all back together turned the 'ign' on and the yellow light came on the relay click off but still no feed to glow plugs whilst the yellow light is on, i'm gonna check and clean all wires this afternoon and i'll keep you posted thanks again Ewen!.

Matt

[ewenmaclean]

Hi Matt,

the "T" pin is a temperature resistance reading - what happens if you disconnect the temperature sensor altogether? That should give you the longest glow duration - light should stay on for 20 seconds or so (depending on relay). If you've got continuity through pins 87 and 30 and continuity to the plugs I don't really understand why you're not getting power there. Where abouts are you taking the reading to the plugs from? You should disconnect one plug and test the little copper clip inside that - the plug bodies will be earthed.

Ewen

[Rustwagen]

Hiya Ewen
Cleaned all the connections and lashed WD40 everywhere it now starts fine! must've just been loose or dirty any way for thanks the electronics lesson much appreciated! just a bit of welding, a headlight bulb, a couple of rear box mountings and its back on the road!!!!!!!!!!!!
Matt

[ewenmaclean]

Hi Matt,

thanks for reporting back and well done for sorting it out. Good luck with the rest of the jobs!

Ewen