Rear Fog lights / Horn not working

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alangs1200
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Rear Fog lights / Horn not working

Post by alangs1200 »

So both these parts were working fine until I fixed a faulty instrument panel lighting issue a few weeks back - turned out the wiring had been pulled off the back of the rheostat when I'd installed a new head unit a few weeks before that. So, logically I disturbed something in that process as neither are now working. Seems that each time I do one thing I screw up something else!!!

For the rear fogs - the bulbs are fine (I swapped with the functioning indicator bulbs to test); the fuse is fine and I've put a new relay in for good measure. Beyond that m knowledge does not stretch!

For the horn - I checked the fuse and replaced the relay. And again, there my knowledge stops.

Thoughts and advice much appreciated.

Thanks
Alan
1993 - parted with an Excel Celebration to make way for kids. 2020 - parted with the kids to make way for an Excel SA.

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Hawaiis0
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Re: Rear Fog lights / Horn not working

Post by Hawaiis0 »

Which fuse did you check?

No 24 is common to both so check that and check supply at fuse holder.
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Re: Rear Fog lights / Horn not working

Post by alangs1200 »

Thanks. I'll double check that tomorrow.
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Re: Rear Fog lights / Horn not working

Post by Johnwindwood »

Our horn stopped working. Turned out that the cigar lighter had shorted (Same fuse). Disconnected it and problem solved.
Kind regards

John

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alangs1200
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Re: Rear Fog lights / Horn not working

Post by alangs1200 »

Thanks for the suggestions so far. Sadly I don't think that cracks it. Fuse 24 is fine (I'd already checked it, but did a double check this morning). The cigar lighter also seems fine. The fuse is working and the socket charges my 'phone without a problem so I can't see that it could be shorting. But if anyone with greater knowledge thinks it could be working and shorting at the same time then I guess I can remove it to check.

So with those things double checked I think I'm back to square one and seeking any suggestions.

Thanks!!
1993 - parted with an Excel Celebration to make way for kids. 2020 - parted with the kids to make way for an Excel SA.

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Re: Rear Fog lights / Horn not working

Post by Hawaiis0 »

looking at the diagrams....

Checked voltage at the fuse base?

It comes through the fuse, splits to HRS switch and base of heater relay . Direct feed Piggy backs the relay base to horn relay base to rear fog relay with out interruption via a GREEN wire.

Check green wire voltage at fuse and then at 3 relay bases:
Heater relay
Horn relay
Rear Fog relay

Although 2 types of relay (4 or 5 pin) connection is to terminal 85 on all 3
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Re: Rear Fog lights / Horn not working

Post by Hawaiis0 »

As both fogs and horn are inop, most likely be near the horn relay - unless we are dealing with multiple faults.

Good luck

Stu
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Re: Rear Fog lights / Horn not working

Post by alangs1200 »

Thanks for that. A job for tomorrow! (if the weather is kind!).
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Re: Rear Fog lights / Horn not working

Post by CHRISYD »

does the fog switch light up when on? if not see if the plug came off the back of the switch. it can be disturbed if removing cluster panel. Horn, did you remove the steering wheel to get to instruments? if so did you put the wire back onto button.
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Re: Rear Fog lights / Horn not working

Post by alangs1200 »

Thanks for the suggestions so far. I've spent a couple of hours with a multi-meter this morning and have worked through these suggestions.

1. All the central dash switches (Ice warning - it was handily cold this morning), HRS, Front & Rear Fog lamps all light up and I've visually checked that these switches are all firmly connected at the rear.
2. I have 12V at the base of fuse 16 which is the one that feeds the Horn relay.
3. I have 12V arriving at the horn relay (arrives at terminal 30 according to my wiring diagram)
4. I have 12V arriving at the rear fog lamp relay (arrives at terminal 86 according to my wiring diagram)
5. I have 12V arriving at the back of fuse 20 (rear fog lamps)
5. I have 12V arriving at the fan relay (which is what I take it you mean by the heater relay as it's the only relay on the heater wiring diagram for my car) - this arrives at terminal 85 according to my wiring diagram.
6 I also have 12V arriving at the connector block under the steering column via the Purple/Black wire heading to the horn switch.

The entire heater / fan system is working fine so I assume the problem must be before the feed to the relay for the fan.

I've never had the steering wheel off so I think it unlikely the horn switch is disturbed (though anything is possible) and so far as I see on my wiring diagram if this were a problem it wouldn't affect the rear fog lamps (which could of course be a separate problem).

If anyone has one (or more) ideas I'd be incredibly grateful!

Thanks.
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Re: Rear Fog lights / Horn not working

Post by AndyC »

There is a multiplug, on the way to the steering wheel and it could be partially disconnected, it's one or two screws IIRC so might as well try there. One screw that holds the upper and lower shroud together round the column, one screw much lower down the shroud that holds it in place. I'd check there with a simple unplug and reconnect, if that does nothing then check whether power getting there to the switch and from switch to the start of those wires leading to the relay.
No "they all do that, it will be....."coming to mind unfortunately. Best of luck.

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Re: Rear Fog lights / Horn not working

Post by Hawaiis0 »

Let's work the Fogs:

alangs1200 wrote:
Tue Dec 29, 2020 14:07
Thanks for the suggestions so far. I've spent a couple of hours with a multi-meter this morning and have worked through these suggestions.

1. All the central dash switches (Ice warning - it was handily cold this morning), HRS, Front & Rear Fog lamps all light up and I've visually checked that these switches are all firmly connected at the rear.
Good. Illumination supply and earths for the switches is separate to the operational circuits
alangs1200 wrote:
Tue Dec 29, 2020 14:07

5. I have 12V arriving at the back of fuse 20 (rear fog lamps)

Supply from 5. above should go to rear fog switch pin 1 and out on pin 2 to Fog lights via RED / YELLOW wire. Please confirm .
Then check earths at each Fog light cluster.
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Re: Rear Fog lights / Horn not working

Post by alangs1200 »

Fantastic. Thanks. Following your advice I was about to put the multimeter on the back of the rear fog switch and test the output from connector 2 when I noticed that there wasn't a Red/Yellow wire. Closer inspection revealed that the connector for this switch had been swapped with the one for the HRS. I double checked with the picture I took before I disassembled this and can only conclude that the rear fogs have never been working since I purchased the car as I had put the three block connectors back as I'd found them and photographed them. I think I can therefore at least blame this on the PO!!

As for the horn - nothing's changed but it probably narrows the options!

A super big thank you for all the help. 1 down, 1 to go!
1993 - parted with an Excel Celebration to make way for kids. 2020 - parted with the kids to make way for an Excel SA.

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Re: Rear Fog lights / Horn not working

Post by alangs1200 »

Looking at the wiring diagram for the Horn circuit, given that I know I have power to the relay and power on the Purple Black wire (at least as far as the connector block under the steering column) then next must be to check whether i have power on the purple/yellow wire to compressor. If I do then I either have a faulty switch, faulty compressor or a dodgy earth on one or both of those. I think!
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Re: Rear Fog lights / Horn not working

Post by MetBlue »

You say at the start of the thread that the horn was working.
Are you certain that the only things you worked on were inside the car ?
It is not difficult to access the horn compressor in the near side head lamp pod. If you have a simple electric horn, ( failing that a bulb and holder) unplug the wires from the compressor and see if the signal is reaching the compressor.

My horn wasn't working, but the compressor polarity had got switched, so it was sucking instead of blowing !!!
There's also the slim possibility you have been unlucky and the compressor has seized since you started playing.

Tony
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