Technical Anyone know where the glow plug relay/control unit is, 2018 MJ Panda?

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Technical Anyone know where the glow plug relay/control unit is, 2018 MJ Panda?

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Last year I replaced a failed glow plug (easy to do - see my guide> Panda 2012+ Replacing glow plugs, 2018 Panda MultiJet :)

This past week the car is again saying 'check glow plugs' and flashing the glow plug light. I've checked all four and the resistance (each around 2 ohms) shows them all to be OK. So, next place to look is the relay unit and wiring to/from it. I know what the unit looks like (thank you Google!), but can't see where it hides... anyone know?
 
Last year I replaced a failed glow plug (easy to do - see my guide> Panda 2012+ Replacing glow plugs, 2018 Panda MultiJet :)

This past week the car is again saying 'check glow plugs' and flashing the glow plug light. I've checked all four and the resistance (each around 2 ohms) shows them all to be OK. So, next place to look is the relay unit and wiring to/from it. I know what the unit looks like (thank you Google!), but can't see where it hides... anyone know?

10 years ago they lived on the battery tray,

Tip:
Follow a RED cable from the battery terminal.. That is the supply 😉
 
10 years ago they lived on the battery tray,

Tip:
Follow a RED cable from the battery terminal.. That is the supply 😉
Yeah - looked all round there and can't see anything. Doubt it's direct from battery as there's a 50A fuse for glow plugs in the undebonnet fuse box, so it would come from that I think. It all starts fine... so can wait until (well) after Christmas now :)
 
Yes, but my car’s not a 2008 Doblo… :)
The photo shows arrangement on my Panda. Big red wire heads to alternator. Other two both go off into the loom or that main fuse/relay box before going anywhere else. The relay looks like this (with two plug in connectors, not a bolted 12v feed) https://cdn.autoteiledirekt.de/thumb?id=8449831&m=0&n=1&lng=en&rev=94077849 - but where is it??
 

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Update: I have now found the relay and control box! At least, in a photo. It is very well hidden!!

It is beneath the battery, (as @varesecrazy suggested), but not connected direct to it, and you can only reach it if you remove the battery, the complete battery tray and associated ECUs attached to that, push other wiring connectors out of the way, and then you can, just about see it!

I was helped by this diagram from ePER, where item 1 is the relay/controller. Take note of the metal bracket, item 3... (which I thought I'd seen before somewhere)
1703675466230.png


That bracket can, just about (!) be seen in my photo from an older post about sorting a stiff gear change, pasted here. It's as if that bracket was designed for something else, and so most of it isn't used!

1703675913887.png


The wiring to the relay/control unit comes up from underneath: there are two plugs (apparently): one connected to the glow pugs and the other to the main engine ECU via the wiring loom to the big plug top left of the photo. According to the circuit diagram in Haynes AutoFix, there are inputs to the glow plug control unit from several sensors (air temperature via the MAF sensor, oxygen sensors above and below the diesel catalyst, the 'variable nozzle turbo motor', and the oil pressure control valve) and it appears to use these to decide if the plugs need to be heated, and for how long – the days of a simple timer for glow plugs seem long gone! I haven't actually been to look at it in the car (it's raining again!), but suspect it might be easier to reach from underneath after taking the 4x4 undertray off? All I want to do is check continuity from the plug on the relay to the glow plugs themselves...


The photo above is the view AFTER taking out the whole battery tray and main ECUs. Here (below) is what it looks like while they are still in situ -- which explains why I couldn't see the relay unit! (The 'unrelated plug' from the photo above can be seen at the bottom of this second photo, where it's been unclipped from a bracket on the side of the battery tray)

1703677389466.png
 
Well done for locating the thing 👍

Have you already checked voltages at the fly leads for each glow plug?

It would be interesting to compare those with the boxes outputs 🤔
Can't really do that as the relay turns off after just a couple of seconds (or at least, inside the car the glow plug light goes off -- and then comes on, flashing a few moments later with the message 'check glow plugs'). I was hoping to be able to check continuity of the leads from the plug that connects them to the controller.
 
Resurrecting this thread as I realised I didn’t report on the outcome.
The previous time I had a glow plug issue it was easy to locate because the plug was open circuit - basically the heating element inside had ‘blown’ like a lightbulb.
But this time, all the plugs reported a small resistance (an ohm or two) showing them to be fine.
I bit the bullet and bought a license for MES on the iPhone (already had the free trial copy). It reported ‘glow plug 4 shorting to earth on heating’, or words to that effect. Glow plug 4, the right hand one nearest the battery, can, just, be removed and replaced as in my guide… but, you have to unscrew the plug ‘just enough’, then take the socket and universal joint off, as otherwise they end up jammed against the turbo! The loose plug can then be unscrewed with fingers.
Duly replaced and all was well. I know I’ve said MES doesn’t always pinpoint the fault, but it did here - and was the only way I could come up with to test the plugs while actually heating.
 
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