Parking Sensors And Sidelight Bulb

[ridway]

Can anyone suggest a cure to this one?

 

The bulb failure warning stayed on over the weekend after driving off (and using the footbrake) suggesting another bulb had failed. Sure enough the nearside taillamp was out. Bulb replaced, satisfactory. All appeared well until reverse was selected. I then got the dredded constant tone, nothing in the proximity zone. Out of curiosity, after trying all the usual bending of the tow ball plug bracket, cleaning the sensors, evicting the spiders etc. I tried putting the old duff bulb back in the sidelight socket. The parking sensors then worked fine.

 

Curiosity deepening I tried it with the bulb removed, the fault returned, constant tone. Tried another new bulb, same problem. I have had a really good look at all the surronding wiring, bulb holders and connections but all looks fine. Everything at the back works fine. No strange symptoms or dimming of lights when the brake light or indicator light is pressed or switched on. Wiper, window heater and even the towball socket all work fine. I have checked tailgate wiring as well, the bit that breaks, all is fine.

 

The sensors worked fine when the bulb was ok last week and the car has'nt been out or even stood in the recent rain.

 

I dont know if this is relevant but the day before I got a low coolant warning and a STOP command. I did stop and the coolant was low, not excessively. It took half a kettle full. There are no leaks and it must be the first time I've put some in since last summer. The added water cancelled the warning sucessfully, no problems since. I'm sure this is a coincidence, but someone may know different

 

Help! I'm lost for an answer.

 

Rich