Big Car Club - MPV and SUV Forums

Some advice requested.

I have the common issue with my Galaxy's parking sensors - the long bleep when activated followed by the dash switch light flashing.

To try to resolve the issue I went round on hands and knees and found that one of the sensors at the rear wasn't clicking - all the rest were so I was initially hopeful I'd found the problem.

Ã,£20 for a secondhand replacement from eBay .. plugged it in and no different.  Also the replacement wasn't ticking.  To see if this was also faulty I swapped the new sensor with another -  now it did start clicking and the previously clicking one in the faulty position wasn't.  So the issue seems not to be the sensor but the location which leads me to suspect the wiring.  I put a meter on the two out pin connections and I see 11.4V; the same as the connector to which the sensors click if connected.

Where should I check now for wiring problems? Do they go directly back to the control module under the passenger seat or are there joins along the way? Is there anything else I can check with just a DVM?

Thanks in advance for any help or replies.

JRWR

Hi - 11.4V should be fine for the circuit, the three pins are ground/supply/signal so if you have a good supply and ground then the signal could be the fault however that's generated by the sensor so that wouldn't explain the lack of ticking. That said the tick test should be used as a crude test though, its not conclusive so a VCDS scan would be recommended.

Wiring wise there is a joint in the tailgate area and then its strait down to the controller although I've only ever seen faults with the wiring at the sensor end, normally within about 10cm of the connector where it loops in from the loom. So check here carefully as its also possible the insulations just cracked and allowed water in to corrode the cable core.

If you do want to locate the connector then lift the carpet and underlay from the tailgate end. The loom enters the cabin almost centrally and then runs off to the passenger side.  You'll find the connector under the underlay and its 6 pins as the supply and ground are common across the sensors. If you do locate it then yes, another check you can do is to measure for continuity and high resistance between the loom connector and the sensors connector. If you let me know which one is causing the problem then I can tell you the wiring colours you need to check.

Thanks Mirez

The 11.4V is with no load so there could be a high resistance which will have no effect on the measured voltage until the sensor is connected and is drawing some current.  I shall test the supply on load if I can and also measure to see if there's a high resistance from the connector in the tailgate area to the actual sensor connector.

The one that's failing is the third fron the left (looking at the back of the car) but if it's a supply issue and they're commoned up I should be able to deduce which wires they are.

Thanks
JRWR