Strange one this.My parking sensors (front and rear) stop working in the hot weather such as we have been having in the UK for the last couple of weeks .When the weather cools down they start working again.The same thing happened last summer.When the fault occurs there is no clicking from the sensors which makes me think that it may be an intermittent problem with the module. But why would it be hot weather dependent ?
Anyone else had this problem or can offer any ideas ?

 

Blues Boy, what you are describing is almost classic symptoms of a broken solder joint. Unfortunately, this involves pulling the module out and pulling the plastic casing off to look at the board itself inside. Having a magnifying glass is going to be helpful. What you are looking for is one of the joints (most likely by the plug) is going to have a black circle in the solder. This is actually a crack. That joint would need to be resoldered to establish an electrical connection again. Not a hard job. But, can be very tedious as you are looking at hundreds of solder joints to find the one or two that have these "cracks" in them.

In short what is happening is when it is cold out, the board flexes one way and this causes the solder joint to make an electrical connection. But, when it gets warm, the board flexes the other way and this causes it to break that electrical connection. Not sure what your soldering skills are. But, having some is going to be kinda needed for this. Big thing is to not apply too much that you start bridging other stuff together. That is when all hell is going to break loose and get some really strange happenings going on.

 

Thanks Thermo,that makes sense.
.To be fair my soldering skills are probably not up to that.Reckon I might pick up a second hand module on ebay.Seems to be some around the £60 mark from sellers with decent feedback.
When I got the car nearly 3 years ago the sensors didn't work as some clown had tried to use the wiring from a Mondeo to the rear ones. !