Thread: Puma reverse light working intermittently

Sorry missed this thread somehow....

Well ideally you need a test light to see if there is voltage at the reverse light.

BUT, the reverse switch on the gearbox is on the passenger side, just behind where the gearshift stick sits, looking from underneath the vehicle, you will see a big thick electrical harness in plastic conduit. the reverse switch maybe hidden from you by this harness. When you find the plug, give it a push, or unplug it (pressing clip on top of plug and wiggle wiggle it out, they are difficult to unplug), give it a spray with some contact cleaner (brake clean) and plug back in.

Thanks Dazza for the advice. I tested the rear light with a voltmeter and had virtually no V. I tested the fog light and was getting close to 12v. I found the reverse switch under the driver side, wiggled the contact out (you’re right, not easy) and sprayed with some contact cleaner but no luck with the light. I couldn’t loosen the switch plug from underneath the vehicle so couldnt check this. So I’m thinking the issue could be either the switch itself or the wiring to the reverse light. Would that be a fair assumption?

Intermittant fault suggests an earth issue to me. Or a broken wire.

1. Go to Battery junction box (normally under seat) and check fuse F10. It's a 10 amp fuse. Your symptoms suggest this should be OK.
2. This makes a connection at the black plug, conveniently named C0570C-23 (pin 23). This is a thin Green / purple wire. Check that the terminal hasn't backed out of the connector (I've seen this before in older cars). Both on the male and female sides of the plug.
3. Find your way under car, to Passenger side of the gearbox, there is a 2 pin plug. Power goes IN via the green/purple trace wire, and when in reverse power goes OUT via the Green wire. Simples.
   
   Check for power on the green/purple wire. Check for power again on the Green only wire when the vehicle is in reverse (ie switch activated). This will rule out the switch being faulty. If NG, replace.
4. This Green wire then interfaces with the chassis harness back in the fuse box area, in the Grey, 24 pole connector, C0376. The output is a grey wire, which will be pin 8 on the respective other side of the harness (this varies depending on which wheelbase variant you have). So again, you should see 12V here if the switch is activated.
5. The grey wire will terminate all the way at the back of the vehicle in the reverse globe holder housing. Check- do a multimeter continuity check between both ends. Bonus tip-wiggle the cable (IIRC, on the 90 at least, it's the cable bundle that is in the Passenger rear wheel arch). Check for obvious damage- tyre wearing thru harness, sticks, broken stuff etc. Elementary stuff Stevie Wonder could manage.
6. The black wire of the reverse lamp globe holder goes to earth. This shares a solder joint in the harness with a number of other things (Tail lamps, rear high mounted brake light, rear window demister) ... so a fault here in this solder joint would also affect earth on those circuits too. The small 1.5mm2 CSA black wire, is solder joined to a 4mm2 CSA black wire, which is the final earth point in the circuit. Not sure where this is located, but it'd stand out if the harness was stripped.
7. The earth is terminated in a ring earth terminal, Named C0565, located on the Driver's side of the transfer case housing. Can't miss it, big black wire, M8 bolt holding it on. Do your due dilligence and remove / clean / reinstall this.

Some comprehensive instructions TA, much appreciated, I’ll follow these through.

I thought I found the reverse switch under the driver side (see pic below) but appears I identified it incorrectly according to the detail above?

If not that might be the centre diff lock switch.
It wouldn't be the first time there is variation between years, models, and the parts they had lying around etc.

The diagram looks like this. Your mileage may vary. But the concept is there. Wiring colours should be preserved.
If I were a gambling man, I'd go straight to the earth point on the T-case.

Just had the exact same issue, replaced the $28 switch and hey presto works like new.

You can do it from underneath, 22mm spanner and skinned knuckles but all in all 10 min job and a heap of swearing.

Cheers Mal

Originally Posted by malsgoing130

Just had the exact same issue, replaced the $28 switch and hey presto works like new.

You can do it from underneath, 22mm spanner and skinned knuckles but all in all 10 min job and a heap of swearing.

Cheers Mal

Partnumber Mal?

Originally Posted by DGatNgala

Some comprehensive instructions TA, much appreciated, I’ll follow these through.

I thought I found the reverse switch under the driver side (see pic below) but appears I identified it incorrectly according to the detail above?

No, as you stated thats on the drivers side, you want the passenger side.
If you look at Toxic_Avenger's post, he gives a clear picture of exactly what I have described, big electrical harness in conduit may hide the switch from below.

P.S The earth is on the drivers side as stated, just out of view on the pic above, side of the case. Its a pretty important earth lead and causes mind boggling issues if loose or has been left off after a repair