Reversing Sensors Long Bleep Help Required

[dionh]

Well, there's nowt so queer as cars! I have now solved the problem of the cd changer not being recognised by the head unit.
It so happens that the other problem with my car was that the parking sensors weren't working (long beep on engaging reverse). So I took off the rear bumper and unwrapped the loom and found that the wiring had corroded in the usual places. Repaired the loom and put it all back together with huge anticipation of it now properly working. No such luck - still the long beep.
Went to the pub feeling depressed, the radio came on so switched it off, but then a miracle occurred - the cd came on. What joy, what bliss! Can't imagine what I did to fix it but that's cars for you. Now all I have to do is to get the parking sensors to work. Any suggestions gratefully received.
Di.

[JohnDotCom]

I have given this its own Heading and Moved it to get it its own answers.

[Greeners]

I would plump for one of the sensors being very wet.

Try poping all four out and putting them somewhere warm to dry out.......Indirect heat like a radiator works well.

[Keith]

First thing to do is listen to each one for a clicking noise then if just one is faulty swap it with another and see if the fault goes with the individual sensor or if not check the wiring again with a multimeter for any that don't click

Each one has three independant wires one of the brown wires is on its own at the multiplug end and seems more vulnerable than the others

I have just replaced one sensor on my Tourer as it definately had gone intermittent internally, it worked 80% of the time but got binned as soon as I manged to pick up a set of brand new ones on Ebay and that still leaves me with three brand new ones in primer for a rainy day!

[dionh]

Latest news - I am more confused than ever!
I checked the PDC wiring again today only to find that I hadn't joined up the connector from the loom to the car (don't say it......., I know). So I now have the parking sensors working again and great rejoicing throughout the land. However the ....ing cd changer is now not being recognised again.
There is obviously a connection here somewhere but I am damned if I can find out what it is. Or is it a further proof of Newton's third law: 'For every action there is an equal and opposite reaction'.
More frustration,
Di.

[Greeners]

Is your cd changer in the boot ?

[dionh]

David,
Yes, it sits on the same bracket as the PDC control unit.
Mk. 1 ZT-T with Kenwood head unit and CD changer.
Di.

[Greeners]

The PDC has two plugs, one black and one white.

Try and un plug each in turn and check the CD changer to see if it works. The black one provides the 12v feed and feed to the sounder, the white one goes to the sensors.

[dionh]

Originally Posted by Greeners

The PDC has two plugs, one black and one white.

Try and un plug each in turn and check the CD changer to see if it works. The black one provides the 12v feed and feed to the sounder, the white one goes to the sensors.

I suspect it will work if I do this, but then what?
The present state of play is:
PDC connected - parking sensors work but CD not recognised by head unit
PDC disconnected - CD works but no parking sensors

Or am I missing something?
Di.

[Greeners]

Originally Posted by dionh

I suspect it will work if I do this, but then what?
The present state of play is:
PDC connected - parking sensors work but CD not recognised by head unit
PDC disconnected - CD works but no parking sensors

Or am I missing something?
Di.

Just above the CD changer and PDC is an earth bolt that they share, other then that the 2 circuits aren't( from memory) connected other then at that point.

If you take out the black plug and it works then the fault is beyond that point. If you put the black plug back in and withdraw the white one and it works, then the fault is in the loom and / or one of the sensors.