Reverse lights not working,bulbs and fuse good, any tips grateful, happy new year XJ40 owners, thanks 1991 Daimler.👍

XJ40
21

OK, I’m gradually drawing the following conclusions -

  1. If grounding the Slate/light green wire from the BFMs at the 24-way Yellow connector under the centre console doesn’t energise the reversing light relays in the BFMs (which suggests that the problem therefore is not in the TRS) and there is continuity between pin 8 of that connector on the Slate/light green wire all the way back to pin 2 of the 15-way black connectors at the BFMs - and
  2. You have battery voltage from fuses A7 (LH) and B7 (RH) in the fuse boxes to the rear BFMs (as proven by the stop and turn lights working) - and
  3. You have ignition-switched voltage via fuses #1 and #2 in the centre fuse box to pin 2 of the 6-way black connector at the LH BFM and to pin 2 of the 4-way black connector at the RH BFM - and
  4. All the Turn/Tail and Stop lights are working correctly - then

If the reverseing lights and the rear fog lights are still not working there must be a double fault in both rear BFMs in that their respective relays within the BFMs have both failed.

Highly unlikely! :slight_smile:

22

One more fog light WAG :grinning:… the bulb sockets have oxidized/corroded and the bulb(s) are not making good contact or the bumper wires are unplugged/broken/disconnected …

23

Ok, this is weird, no power at all fuses left and right sides, only centre fuse box circuit 3 ?

24

Sorry, don’t understand.

Do you mean that you have no 12 V battery power to both left and right fuse boxes at all on any fuse therein?

“Circuit 3” is the entire centre fuse box which is ignition switched via the ‘Ignition ON’ relay - and you do have power to that box?

25

Correct, mystery. L/R fuses powerless.:thinking::slightly_frowning_face:

26

If the centre fuse box is getting Ignition-switched power then the battery feed to the Ignition-ON relay must be good so the absence of battery power to the left and right fuse boxes has to be wiring to or solder joints on the fuse box boards or perhaps corrosion at the positive stud eyelets on the firewall under the dash.

Or your voltmeter is on the blink! :slight_smile: