Sources for parking sensors

[carrera]

Messing about with my borrowed Tech 2 this afternoon I discovered that I have two parking sensors that are not working correctly. Objects are detected 15 to 30cm away when nothing is there.

Are there any decent aftermarket sources, I'm not fancying the prices for Saab sourced components ?

[phoenix]

They do come up used on eBay from time to time. But it's also worth taking them out of their housings and cleaning up all the crud that accumulates.

[carrera]

Thanks

I did try the highly technical wet finger to clean the outer face of the sensor approach    Is there more to the cleaning than that ?

[sgould]

When I took the back bumper off my car to sort out the tow bar rust, I found the parking sensor loom connector, that is attached to the end of the metal bumper bar, completely buried in a ball of damp mud.  I cleaned it up and sprayed the contacts and put it back together with silicone grease. There were odd errors before, but none since.  Could have been coincidence though, as all the connections were cleaned. But the individual sensor connections looked OK.

[phoenix]

Yes, there's a sleeve around the sensor. And as Will says, you can also get corrosion in the inline connector.

[carrera]

OK, something to do later on maybe. At the moment I'm diagnosing the fault with the button in the centre console that will lock but not unlock the doors.

What a ?>^&$ job getting the ashtray out, when you don;t know what to do. After final extraction I now know that having removed the outer tray, a small screwdriver to pull inwards the left and right hand side pins to dislodge them is the key.

All this while waiting for postie for a power supply to get round the TCM issue. I suspect I am going to be suffering from First Class Fail syndrome, it was posted yesterday, but no postie in the street.

[carrera]

Centre lock button sorted. I was about to attempt dismantling of the switch as it was showing a high resistance of about 60 ohms. It was proving a little difficult so I decided to give it a dose of contact spray. Sorted 

The reversing sensors proved more difficult. I managed to remove the bumper cover, extract the sensors, give everything a clean, including the connector, but I am still left with two failing sensors. On will not read beyond 30cm, the other, which was doing the same now detects nothing and stays at 255cm

I have swapped positions and the fault follows the sensors

Time to reassemble, possible further electrical checks to be performed on the sensors, just for education

[sgould]

When I got the new sharkfin last month, it was sent First Class on Friday lunchtime and arrived midweek the following week.  It seems that stuff taken to post offices is only being collected three times a week.

I got some replacement sensors from Suffolk Saab.  Not the cheapest, but almost new.  He has parts for the later Saabs too, which many breakers keep away from.  Although these days all Saabs are "a bit old"...

[carrera]

So the range of resistance values between pins 2 and 3 (signal and earth) was 940 to 1020 ohms, and there is a diode in here as it only tests one way. Between 1 and 2 (feed and signal) it started out with a negative 50 ohms and dropped 1 ohm / second until I got bored. I don't know what type of circuit does that. 

I ordered a couple of service kits from Bill last Thursday, first class with the next day being Good Friday. They arrived Saturday morning 

No postie today in the street though. Didn't have any letters yesterday either.