A problem has just developed in our 2010 Jayco Discovery while we are on the road. 12 v power to van from spare battery in car is no longer working, but all driving lights etc are OK - only the 12 V to internal lights, pumps, fridge, so can't free camp easily. All work OK when hooked up to 240V. Has worked fine up to now, so sounds like a connection has come loose. But can't see where the power supply unit is, to check for loose wiring/plug. 3 week delay to get checked at Jayco agent where we are currently, so need to see if any simple solution so we can keep moving. Any suggestions how to inspect power supply unit in van - seems to be mounted below fridge, but no obvious way to see it, short of removing fridge?
12 volt power not getting to van
- Thread starter Jimbogan
- Start date
Thanks all for comments. Power is OK at the car plug and also at a junction point under the van, so fails somewhere between there and the SETEC. Fuses all OK, and everything in van works OK when connected to 240 V. Have removed the small screw in the panel below fridge, but panel is refusing to come off, so maybe there is some special knack to removing this? Have levered with a screwdriver, but is bending without yielding. Not keen on breaking it!
By your first post i assume you do not have a battery in the van and rely on power from your vehicle when off grid ?
If that is the case the there are really only three places to check for power coming to the van.
First stop is the trailer connector. Trailer plugs are notorious for bad connections so you will need to check that power is getting across to the van side and not just if it is available on the vehicle. The best way to do that is remove the cover on the van plug and check that power is on the correct pin while it is plugged into the car.
If power is showing up there take note of the size and colour of the wire to help you to locate it later.
The other two areas to check are at the setec and at the "birds nest" where the wiring from the trailer plug terminates.
On the setec you will need to check if power is available on the connection marked "Aux in +VE" see this thread for a picture of the setec that shows that connection. If power is there and you have checked all the fuses then you may have an internal problem with the setec...... probably best to see a dealer.
if no power at that connector the again take note of wire size and colour and find the birds nest, usually located on the right side chassis rail. look for a mess of wires all jumbled together (thats why it's called the birds nest) and usually covered by a steel plate. once you have located it check for the two joined wires that match the ones you looked at earlier. check for loose connections and test for power on both sides.
Also make sue your earth connections are ok. It would be most unusual for any of the wiring to break inside the loom unless you have had work done that may have drilled into or cut the loom.
Let us know how you get on
Edit: Just read you other post and see you have already done most of the checks so you really need to try and trace the wire back from the setec and see where the break is. I will leave my post as it may be of use to others.
If that is the case the there are really only three places to check for power coming to the van.
First stop is the trailer connector. Trailer plugs are notorious for bad connections so you will need to check that power is getting across to the van side and not just if it is available on the vehicle. The best way to do that is remove the cover on the van plug and check that power is on the correct pin while it is plugged into the car.
If power is showing up there take note of the size and colour of the wire to help you to locate it later.
The other two areas to check are at the setec and at the "birds nest" where the wiring from the trailer plug terminates.
On the setec you will need to check if power is available on the connection marked "Aux in +VE" see this thread for a picture of the setec that shows that connection. If power is there and you have checked all the fuses then you may have an internal problem with the setec...... probably best to see a dealer.
if no power at that connector the again take note of wire size and colour and find the birds nest, usually located on the right side chassis rail. look for a mess of wires all jumbled together (thats why it's called the birds nest) and usually covered by a steel plate. once you have located it check for the two joined wires that match the ones you looked at earlier. check for loose connections and test for power on both sides.
Also make sue your earth connections are ok. It would be most unusual for any of the wiring to break inside the loom unless you have had work done that may have drilled into or cut the loom.
Let us know how you get on
Edit: Just read you other post and see you have already done most of the checks so you really need to try and trace the wire back from the setec and see where the break is. I will leave my post as it may be of use to others.
Last edited:
Wow, a great reply @boots33! After all testing, I decided to go back again and start at the battery in the car. Found that a fuse in the positive lead line had blown. What I thought was power at the trailer connector was not the 12V supply to the van, but one of the other circuits. So thanks for all your comments and ideas - I've certainly learnt a whole lot more about the wiring and power supply in my van in trying to track down the problem.
