Parking aid sensors, but not working & no dash switch?

[iangalaxy]

Hello all, I'm wondering if anyone can help with an issue I have with the used 2007 Galaxy Ghia I've recently purchased.

On the dash there is no button to activate/deactivate the parking sensors - I therefore assumed that they weren't fitted to my car. However, after a bit of poking around I've found that all the bumper sensors are in place and the control module is wired up in the boot. The parking control module gives a continuous beep for a couple of seconds when I put the car in reverse, which I understand means there is a fault with the system? So my questions are:

1. Should there be a button on the dash? (I have a double-width stability control button currently)
2. What would be the best way to diagnose the fault, assuming there is one?

The car does have a tow bar attached, I'm don't know if this was a factory fit or aftermarket job.

Many thanks for any help!

[mike wilson]

You only get a button for forward sensors.  A quick beep is normal for aftermarket sensors.  Fault beep on factory fit is long enough to teeter on the edge of irritating.  Maybe five seconds plus.

Factory fit adjusts the module to allow for towing - when the electrics are connected, it disables the sensors.  Aftermarket, generally, does not do this.  Sometimes they pick up the hitch, sometimes not.  They always pick up the load but this can be beneficial when reversing as it gives you warning of the load going off-axis.

I assume you've tried backing up to something and no response?  Aftermarket ones can be less sensitive than factory and only start working in the last metre or even less.

Start with simple things.  Wiring OK?  Sensors clicking when (engine off, ignition on) reverse selected?

[iangalaxy]

Thanks for the reply Mike. Haven't had chance to check the wiring yet, but NONE of the sensors are clicking at all, so I'm wondering if they have been disabled somewhere due to an aftermarket tow bar?