Rear Light, Brake Light issue

[JohnJ_5040720]

I've just had a new Tow Bar & Twin Eectrics fitted to my X-Trail by a Nisaan dealership. We're towing for the first time this year on Friday and on checking things out yesterday I noticed a slight problem with the caravan rear lights. When the car lights are switched on, the rear offside caravan light is much dimmer than the nearside. When braking, the rear nearside caravan light is much dimmer than the offside.

Any suggestions? As it's a 20 mile round trip to where the van is stored, thought I'd try and get a few suggestions before I go and have another look.

 

[rob_jax]

John,

Could be several reasons:

Van Light Cluster

If your caravan uses the combined 5W/21W side and brake light, it's pretty easy to insert the bulb the wrong way round - it should be impossible but it can be done.

If your caravan uses separate 5W side and 21W brake lights, then check that the right bulb has been put in the right socket - you'll need to compare with the correctly working side.

Car Wiring:

It could be that the 12N socket has incorrect wiring - look on the Internet for a 12N wiring diagram and check that the right coloured wires go to the right numbered pin.

Or if you have a multi-meter you can simply test with the meter probes and check for 12 volts when the appropriate circuit is switched on. Saves dismantling the socket even though it's only just a few screws.

Van Wiring:

It could be that the van 12N plug has been incorrectly wired, either in the plug itself or in the back of the light assembly.

But this should have been checked by the builder and at the PDI - so this is a last resort.

Robert

 

[greenplum_5088396]

After trying above run a seperate earth from the light that is working OK and see if that brightens it up

 

[Guest]

If none of tha bove works, try removing both rear light cluster lenes on the van. There is usually a spade terminal in one of them that is the main earth for the rear lights. It can pop off and may be the problem.

 

[Matthew_5040954]

worth noting that some car have sensors that detect is a bulb has blown. Because wiring for a towbar is usually wired to the rear light cluster, when the lights are switched on the drain of power trick the sensor into thinking the bulb has gone so reduce the power to prevent other bulbs blowing from the increase in power to them, as there are the right number or actually more bulbs this cause the lights to go dim or not work at all. Found this with my last car, had to have a special relay added to increase the power to the towbar socket when the caravan is connected.

 

[JohnJ_5040720]

Many thanks for all your suggestions.

I'll try and sort it out tonight and let you know the outcome.

JohnJ

 

[BigAl1]

Think you must have a stop / tail bulb in 180 degrees wrong.

 

[JohnJ_5040720]

Thnak sonce again for all suggestions.

Cracked it.

The problem was simply that the bulb was indeed 180 degrees wrong! The bulb holder had shaken loose towards the end of last year, so when I put it all back together, obvioulsy I did it wrong!

Would never have thought of this possibility without the suggestion on this forum.

Lesson learned - always check the simple things first!

 

[rob_jax]

John,

Pleased you got it sorted. It's pretty easy to fault find if you give all the information in a clear and concise manner - exactly as you did.

By the way, when you corrected the "upside down bulb" you may want to look at the contacts and see if they have been bent back. When you fit the bulb the wrong way wound, it goes much deeper into the socket - bending back the brass contacts.

If it's working now it should be OK for ever, but it's wise to check.

Robert