Relay Identification

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When the intermittent wipe and the wipe+wash stopped working on my Xantia, the most likely candidate was the 'relay'. I knew this relay was supposed to be next to the main fuse board under the dash, but it took a lot of research and hunting to find it. It turns out that while Citroen appear to have used only two different under-dash relay mounting plates (at least for Mk1 cars), there were many variations on which relay was mounted where, mostly undocumented!

R1.jpg

This diagram of a Relay Plate, “1995 model year on”, (my 1.9TD sx estate was built in January 1996) is typically misleading:

  1. Any key to the relay layout will probably be wrong for the car you're looking at, just as the one shown was wrong for all four '95-'98 Xantias that I've worked on – all of them different!
  2. It's a schematic layout rather than an engineering drawing. The relays shown as being 'off the board' (15, 16, 17) do not plug into fixed relay bases on the plate, aren't necessarily in the same plane or orientation as the plug-in relays and may not be as close to the plate as the diagram suggests.
  3. Many of the relay positions will be empty – not just of relays but of relay bases too.

As all Xantias have a wiper delay/relay, you might expect it to always be in the same place (Item 12 according to Autodata, the mechanic's 'bible'). Not so, on my car Item 12 is the interior lights delay/timer.









R2.png

The first photograph shows what the Relay Plate actually looks like on my 95/96 1.9TD sx Estate; even if you're looking at the same model variant of similar age, expect the layout to be different! The plate isn't flat and is tucked down below the fascia above the driver's shins. The photo was taken with the camera down on the driver's floor mat – not somewhere you can get your eye!

The brown unit to the right of the fuses that isn't shown on the diagram, is the diagnostic socket.

The orange unit (Item 12) is ?interior lights? relay/delay.

The grey item (Item 14) is the lights-on audible alarm.

The (blue) wash-wipe relay/delay unit for which I was hunting, is in position 15; mounted upside down behind the plate and well-nigh invisible unless you look hard for it. A corner of it is just visible below this green relay.

I only saw it after until I had taken several photos and was trying vainly to reconcile them with the diagram - 12Mpx photos at 1:1 on a 19" screen!.



R3.png

Even in this close up of the lower (relay) section of the plate, the only sign of the front wash-wipe unit is a glimpse of its 'silver' mounting tag screwed onto the plate.

Unplug the green and black relays to get at it.

It became clear that the position of under-dash relays is no guide to which does what on a Xantia. But the good news is that the various 'relays' are colour coded, though with two types of general purpose (multi-use) relays, the colour doesn't necessarily indicate what each one does:

  • Green (multi-use),
  • Black (multi-use),
  • Grey (buzzer),
  • Orange (timer/relay),
  • Blue (wiper relay/timer); the reason why this wiper relay/timer unit is mounted with a tag rather than into a relay base is probably so that the same unit can be used on the rear wiper motor. Unfortunately, as the contact tags partially support the wiring under the dash, this load eventually fractures the solder joints on the relays internal PCB! - which is why they commonly fail.