smokeyone Posted May 20, 2014 Share Posted May 20, 2014 Hello Latest p38 mystery is the horn going off by itself after the car was parked and locked for a couple of hours. To stop the horn I ended up taking out the relay in the fusebox under the bonnet. Could I check that the horn is separate from the car alarm and if anyone can remember if the horn will work or not with the ignition turned off. I am thinking of investigating the wiring under the steering wheel but if the horn does not work with the ignition off it's unlikely to be a wiring problem under the steering wheel - Thanks Quote Link to comment Share on other sites More sharing options...
P38 Paul Posted May 21, 2014 Share Posted May 21, 2014 hello mate , the horn will work without the ignition on & without the key in the ignition , hope this helps , kind regards , Paul . Quote Link to comment Share on other sites More sharing options...
smokeyone Posted May 22, 2014 Author Share Posted May 22, 2014 Thanks for the tip So it might be worth checking under the steering wheel after all ................. Quote Link to comment Share on other sites More sharing options...
Shackleton Posted May 23, 2014 Share Posted May 23, 2014 Mate, it could be something different but this happened to my uncle. EDIT: Just spoken to him. The alarm receiver on the earlier cars doesn't have RF shielding, leaving it vulnerable to wifi signals, radar, garage doors etc. The BECM can be awoken erroneously and can subsequently activate various electrical systems (one seemingly common one being the horn) and drain the battery. He bought a Nanocom and had the security features on the car deactivated. But there are other options: 1. Fit a 2nd generation upgraded receiver, they have RF shielding. The P/N should be YWY500170 2. Shorten (or remove) the aerial from the alarm receiver. You have to be close to the car to blip it open, but it's reported to be an effective fix. 3. This is my own guessing, but I thought car alarm receivers were adjustable to be more or less sensitive. George Quote Link to comment Share on other sites More sharing options...
smokeyone Posted May 23, 2014 Author Share Posted May 23, 2014 Thank you for the advice - I will double check but when I had both ecu's repaired some months back I had the chap de activate the alarm altogether - figuring the alarm was more trouble than it was worth and all the fun of changing flat batteries etc etc - Would you happen to know for certain if the alarm siren is different from the horn because it is the horn going off if I put the fusebox relay back in - Thanks Quote Link to comment Share on other sites More sharing options...
elbekko Posted May 23, 2014 Share Posted May 23, 2014 I think it can be configured in the BeCM, normally it has a separate siren (with its own battery). You can have a look at this circuit: It's always possible the BeCM is acting up. Quote Link to comment Share on other sites More sharing options...
Shackleton Posted May 23, 2014 Share Posted May 23, 2014 Control module issue sounds like a possibility though as elbekko says. I've no idea about the horn/siren, sorry! Do you still have remote central locking active? Don't know if it's possible to have the alarm deactivated wile retaining use of remote locking; but in that scenario your receiver would still be active and picking up signals. I'll bow out now as I don't know anything about the P38. Good luck. Quote Link to comment Share on other sites More sharing options...
smokeyone Posted May 24, 2014 Author Share Posted May 24, 2014 I had the remote switched off too - just use the key to get in and out - central locking still works though...... Where did you get the diagram from - rave !! Quote Link to comment Share on other sites More sharing options...
P38 Paul Posted May 24, 2014 Share Posted May 24, 2014 hello mate , have you tried swaping the relay for another one ? it might be a easy fix for you . other than that i think i would be looking at a wiring or rotary coupling fault . kind regards , Paul . Quote Link to comment Share on other sites More sharing options...
smokeyone Posted May 25, 2014 Author Share Posted May 25, 2014 Yes, tried changing the relay but no luck - not looking forward to taking the steering wheel apart - Quote Link to comment Share on other sites More sharing options...
elbekko Posted May 25, 2014 Share Posted May 25, 2014 I had the remote switched off too - just use the key to get in and out - central locking still works though...... Where did you get the diagram from - rave !! Yes, that's from the RAVE Quote Link to comment Share on other sites More sharing options...
smokeyone Posted May 26, 2014 Author Share Posted May 26, 2014 Thanks - Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.