Topic

Hi guys, long time since I've posted here, though I've been lurking.

Haven't had much chance to use the TF this year as the weather has been atrocious in Northern Ireland, but had it out last weekend for a run to Donegal. On the way back, had occasion to parp the horn at an oncoming driver who was drifting across the line. Except it didn't work. No sound at all.

Tried it along a quiet stretch of road and it worked on & off. Put the multimeter on yesterday, horns seem to be OK but there seems to be an intermittent connection at the plug. Is this a symptom of failing alternator or more likely just a break in the wiring?

TIA

Could possibly be the swivel joint unit that sits behind the steering wheel, or even a dodgy spring contact on the horn buttons. Worth fetching the wheel off and having a look.
Just remember to leave the battery off for half an hour to let the ABS system to discharge before popping out the airbag in the steering wheel.
Sundance

Thanks Sundance, that's another option. I'm intending to have the wheel off this winter to fit a stereo control to it, but looks like I might have to do it earlier.

Mostly concerned in case I'm going to need a new alt

Edit: if it's a problem at the wheel, I'd guess it's the swivel ring as both buttons are intermittent

Could also be the horn(s).Try the connecting plugs. Are they making a good clean connection? Clean them up anyway.
With the horn(s) disconnected you can put a meter on the plugs to see if the current is getting to them consistently.(Without annoying the neighbours. )

MGs official line was disconnect the battery for 10 minutes before touching the SRS system, personally I just never touch the airbags unless the ignition has been off for several hours.

It wont be the alternator.

It could be a failing relay in the BCU.

talkingcars wrote: wrote:

MGs official line was disconnect the battery for 10 minutes before touching the SRS system, personally I just never touch the airbags unless the ignition has been off for several hours.

It wont be the alternator.

It could be a failing relay in the BCU.

I have had my steering wheel off about three times over the last year, and gave it a good thirty mins of discharge time, it was ok and no airbag accidents, but if you do take the airbag off, handle carefully and do not put it down upside down, cos if it went off, it would be fly!
Incidentally, checking the MG service data, they recommended the dealers changed the airbag modules every 15 years, so most of us are due new ones!
Sundance

If your TF is a 2003 or later with the round key fob (Pektron System) it could well be a failed horn relay which is inside the BCU/SCU. Its a very common failure with the Pektron system.

Brian.

It's an 02, a Lucas not Pektron.

Haven't had a chance to look any further, but might get at it tomorrow. I'll definitely give it a decent intermission between disconnection & discombobulation ????

This may not be relevant to the TF but just in case....

A few years ago I had a Volvo V70 and found when I cause to use the horn it didn't work... The advice I was given was to keep the horn pressed and it will probably come back.
I was doubtful this would work but as it was free and simple it was worth a try, so that night I drove home over the moors and kept my hand on the horn....after 5 mins I started to get a faint 'peep' then as I went on the sound gradually came back to full strength - very strange! but it worked fine there after..

The easiest test is to diconnect the horn and using some new test wires to a power supply ie your battery.......if it dont honk bin it.........ive done simular to chris years ago and the horn did work after a while but made some croaky tones..anyhow if the alarm sounds the horn ok....then the problem is in the steering wheel circuit...

When I bought my f it came with an MOT & several faults which I would have failed it on, like no horn. If your car has the Lucas system then have a go at replaced the multi-function control unit, which is behind the drivers side fuse box, that worked for me. One of the on board relays had packed up & as the control units were buttons it wasn't worth switching the soldering iron on.

Chris P Dash wrote: wrote:

.......The advice I was given was to keep the horn pressed and it will probably come back...

That sounds like your horn had seized up, unlikely in the TF due to it's location but not impossible.