Towing Backup / Reversing Relay ?

[Gazza1]

Hi,
Can anyone tell me where to find the relays feeding the tow 7 pin connectors? I had a short on the reverse light circuit but hasn't blown fuse 28 and the fuse isn't going live when I go into reverse. All the other caravan lights are working. The wiring diagrams imply that the relays are with the fuses but aren't according to the legend in the fusebox.
Ps it's an MY14 Overland.

Thanks Gazza

[drover]

I'm pretty sure the relays are on on the bottom side of the circuit board, if your testing your van lights, unplug and see if the Jeep lights all work, I have found if the BCM detects a fault it will shut down the circuit..... I found a faulty socket for light on van, once fixed everything went back to working again and a faulty led caused the same thing .... Since the fuse hasn't blown it sounds like its shut down, check the 7 pin and reverse lights/sockets on van .

[Gazza1]

Thanks very much Drover, I did wonder if the relays could be on the underside but will have to remove the heavy duty positive to be able to lift it up. The Jeep reverse light is still OK so I will first I will disconnect the vans reverse light wire and check to see if the 12 pin goes high then. You may be right about a fault still being on the van as although there is no longer a short showing it could still be fault as never found out why the short disappeared. I am still getting a fault on my redarc towpro saying I have a short circuit on my brake wire when checking the van 12 pin I found that I had zero ohms on the reverse lights. I suspect where they have joined the brake wire to all 4 brake circuits in the loom they have done a rough job and it is touching the chassis but it is bloody hidden in the A frame so I suspect could be similar with where they have joined the reverse lights as the fault cleared when pulling the wiring in the frame of the van.
Will let you know how it goes.
Thanks again for the help.

[drover]

You do have reverse lights on the van and they worked before I gather ???

If the one on the Jeep work then it is most certainly the van, won't be a dead short usually but the BCM will shut off power to the tow circuit ....

The Towpro throwing alerts, points to the possibility of the plugs being cruddy and the terminals are leaking as the tow pro should be totally isolated from anything else so give them a good look check each wire/connection for good join and not rotten .. if thats okay then look at your rear light housings, for corroded connectors and checking that the leds are not causing the fault.... You won't get any decent continuity tests with leds fitted only terminal to terminal checking wiring.. I chased one on my rig ended up just replacing all the little mongrel leds, that sorted things out.

[Gazza1]

Hey Drover thanks again. Just wondering do you have any tips on fuel economy as mine has gradually drifted up. I used to get 7 or 8l/100 on long runs and about 10 around town. Now it's 11l/100 on a run and 13 around town. I have it regularly serviced so air filter like new and just done another clean of MAP, MAF and EGR tube but it made no difference. Car is still running great but not sure why consumption has gone up.

[2bad4u]

Originally Posted by drover

You do have reverse lights on the van and they worked before I gather ???

This…..

None of my cars have ever had the reverse pin (pin 2) wired up to the lights. Usually it is used as an auxiliary feed, particularly on Jaycos.

As for the Towpro, 2 common faults are bad earth or voltage drop due to incorrect gauge wire.

Fuel economy, probably a build up of crap in the manifold like most modern diesels. Cleaning the EGR, etc., unfortunately doesn’t get rid of the build up in the manifold.

[Gazza1]

I pulled the fuse box out to see if the trailer relays were behind but there are none on the back so idea wherever are hidden. Just incase the legends were wrong I tested every relay and they are all switching with low ohms OK.
Also checked with OBD and the BCM module for trailer backup lights is set.
Need to find this darn relay.