Hi there,

i'am new to all this forum malarky so be kind please, here go's

I have a vauxhall astra h 2008 diesel which has a vauxhall towbar and electrics fitted, but the fridge and battery charger won't work when connected to the car (fuses ok) but if you flick the rocker switch to choose the power supply for the caravan onto car it will power lights etc but not the fridge or charger, flick it onto the correct position to work fridge/charger not happens! The electrical system on the car is a volta and the part number is SIM 8454-1232.

I have trawlled the net and are unable to find any wiring diagrams to see whats wrong, I have printed off a couple of diagrams/pictures of the 12s plug and have checked the relevant pins and i don't have power from pin 2, should it only have power when undeload? does that also power the charger?

Many thanks Carl

Try measuring pin 2 & 6 with the engine running. On most towbar electrics, these will only be live when the engine is running to protect the battery discharging.

the fridge and battery charger supply will only work when the engine is running at a high rev stage or whatever the relay is set at.this is to protect the battery on the car.

Towbar Wiring

Socket and plug wiring instruction

**NB It is essential that pin 6 is wired through a split relay from 1998 on!!

Thanks for the replies guys!

I have today finally checked the 12s socket wiring today and I have a power at pins 4 and 6 with the engine running from idle upto 4500rpm but nothing from pin 2. When I stripped the socket there is no wire to pin 2 (reason for no power) and have checked further up the loom and theres no wire there!

The wire from pin 4 goes to a relay in the boot, would it be ok to take a power from 4 to 2 if i fitted an inline fuse (20amp or there abouts)?

Many thanks carl