Heater plug relay

Talk about the 406's electrical system, what wires do what, how to add extra functionality, etc.

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straggler
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Heater plug relay

Post by straggler » Mon Aug 13, 2018 11:35 am

I've had an intermittent starting problem with my 96 XUDT. Today I discovered the heater plug solenoid is a bit sticky - Sometimes it works, sometimes it doesn't. If I give it a tap I can hear it kick in and the car starts.

Anyway, being a dedicated tight arse I was wondering if a solenoid off an HDI would work (I have an HDI I am breaking for spares)? The part number is different but maybe it will do the job? I also have a 205 1.8 XUD I could swipe the relay from, if that would work.

Or, I can see the solenoid on the XUDT has been apart before as there's a cable tie holding it together. Is it worth taking it apart and giving it a squirt with WD40?

Thanks all!

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steve_earwig
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Re: Heater plug solenoid

Post by steve_earwig » Mon Aug 13, 2018 12:02 pm

HDi relay - possibly. The Xud's is just a relay, while the HDi solenoids are controlled by the engine ecu (semi-mux) or BSI (full-mux), 2 of the feeds are just + & - but the other 2 - worth some experimentation?

As for cleaning it, it's kind of working just now so it is possible to make it worse. Up to you I guess, worst case scenario is you kill it & your car turns into furniture...
Unskilled meddling sin©e 2007

2004 D9 2.0 HDi 110 Estate lhd VF38ERHZF81657352 - sold but being very well looked after.
1991 Yamaha TDM850 - fuel leaks galore!
2008 Toyota Recall4 2.0 VVTI ATM LHD JTMBH31V90D007261 - flimsy piece of crap.
1953 Matchless G3LS - It's alive!!

straggler
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Re: Heater plug relay

Post by straggler » Mon Aug 13, 2018 12:10 pm

Cheers for the reply.

If I fit a non-standard relay is there a risk I could fry something else? Quite happy to plug it in and see if it works, otherwise. The connections look the same.

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steve_earwig
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Re: Heater plug relay

Post by steve_earwig » Mon Aug 13, 2018 12:17 pm

No problem, it's too hot to do much here.

I can't even remember what an XUD relay looks like, maybe it's obvious but I'd hope you were certain which was which. Unfused battery voltage here!
Unskilled meddling sin©e 2007

2004 D9 2.0 HDi 110 Estate lhd VF38ERHZF81657352 - sold but being very well looked after.
1991 Yamaha TDM850 - fuel leaks galore!
2008 Toyota Recall4 2.0 VVTI ATM LHD JTMBH31V90D007261 - flimsy piece of crap.
1953 Matchless G3LS - It's alive!!

PeterN
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Re: Heater plug relay

Post by PeterN » Mon Aug 13, 2018 11:41 pm

It's basically just a high current relay and they are all mostly the same unless it contains any electronics. The usual problem is that the contacts don't make properly, you really need to address them with a fine file or wet & dry paper, sometimes they don't work properly because the heat generated by high resistance contacts melts the plastic and allows the contacts to go out of alignment.

Peter

straggler
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Re: Heater plug relay

Post by straggler » Wed Oct 03, 2018 1:30 pm

I fitted the relay from the HDI and the car fired up straight away. Have tried hot, cold and warm starts and it seems fine. The connections are all exactly the same so maybe it's just minor internal differences? Will wait for the really cold weather before declaring total victory (and carry the old relay around in the boot, just in case) but looks good so far.

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