van rear lights

[DavidW1]

Just got new towcar and have replaced the 12n socket as the old one was very corroded. Everything electrically fine, all continuity OK, earth OK and with car lights on feeds to left and right tail lights are 11v rising to 12.5v with engine running.

Connect to van and flashers, brake lights and fog light all OK but no rear lights.

Have cleaned van plug and checked van rear harness plug - can make rear lights work with seperate 12v battery but not with car socket.

Bailey manual says van lights are earthed through car earth - only thing I havn't tried is actually connecting van to car tow ball but according to circuit info this will not make any difference.

Any clues out there?

 

[antrimboy]

Did you check the earth wire and connections on the car from the socket to the earthing point? It sounds as though the return is not capable of carrying the full load back.

 

[DavidW1]

Yes Eddie, earth wire is substantial to a dedicated point and I remade the conection ensuring clean metal contact.

 

[antrimboy]

Have you checked the battery voltage when idle? 11V.seems very low. I've just been out and checked mine, and it's 12.2 idle, and 14.03 running.Perhaps you're getting too much voltage drop to pins 5 & 7.

 

[DavidW1]

I thought that too but as the tow socket feed is via relays I assumed the relay was controlling the output. Also I can get the road lights to work, albiet dimly, with a 9 volt drill batterry so I think the lowish volts can be ignored.

I have looked at the van circuit diagram again and see that the alarm has a feed via the alarm battery to the road lights. Next stage is to replace the alarm battery and try with the van actually connected to the towball.

Its all good fun! and anyway with this lousy weather a caravan trip can easily wait.

 

[antrimboy]

I thought that too but as the tow socket feed is via relays I assumed the relay was controlling the output. Also I can get the road lights to work, albiet dimly, with a 9 volt drill batterry so I think the lowish volts can be ignored.

I have looked at the van circuit diagram again and see that the alarm has a feed via the alarm battery to the road lights. Next stage is to replace the alarm battery and try with the van actually connected to the towball.

Its all good fun! and anyway with this lousy weather a caravan trip can easily wait.

Wot lousy weather? - It's beautiful over here in N.Ireland - can't wiat to get away at the w/e. It'll probably be pouring it down by then!

 

[DavidW1]

I thought that too but as the tow socket feed is via relays I assumed the relay was controlling the output. Also I can get the road lights to work, albiet dimly, with a 9 volt drill batterry so I think the lowish volts can be ignored.

I have looked at the van circuit diagram again and see that the alarm has a feed via the alarm battery to the road lights. Next stage is to replace the alarm battery and try with the van actually connected to the towball.

Its all good fun! and anyway with this lousy weather a caravan trip can easily wait.

Finally got it fixed and you were on the right track Eddie. It was poor conections in the splicing of the original harness causing low volts; if I had used an insulation tester it would have highlighted the prob. Ayway rewired the car towing circuit and all is now fine