puppysandwich

puppysandwich

New Member
Having picked up the new V8 yesterday, I noticed the cruise control wasn't working, the switch illuminates but the steering wheel buttons don't do anything. This morning I found out the horn doesn't work either so I decided to investigate. After removing the horn I found that the multiplug isn't connected to anything so there is no live feed for the horn and the cruise control switches aren't connected to anything. I removed the cowl and found the female half of the multiplug, tucked up underneath, however, its a different type! It looks as though somebody has changed the steering wheel for either an earlier or later one so the I can't fit the plus together, this isn't a major problem but the length of the cable is. How do these cables run? surely the don't just wind around the steering column as you turn the wheel? If the current multiplugs fitted together I would only be able to turn the wheel half a turn. :confused:
 
There is a device called a 'Rotary Coupler' under the steering wheel so no different to any other disco.
 
No Airbag, and I've now located the correct part from ringing one of the breakers on Ebay.:)

However........... The horn doesn't work by connecting up the wires and pressing the switch, it works by putting wires direct to it and the 12v feed to it is live. Also the hazzard warning lights don't work and if you press the switch when the indicators are on it switches them off. Also if you open the drivers door with the ignition on, the interior lights flash 6 times then go off, and I can hear and feel the indicator relay clicking. The interior lights work fine when you press the switch to turn them on. There's no interior lights on any switches or the speedo etc. All the fuses are fine so I can only think its the Multifunction unit :mad:
 
Normally the horn button earths the horn relay (passenger footwell) so it will switch a 12v to the horn terminals, you should have two horns (300 series).
Dash lights pick up their feed from the light switch.
if your MFU is faulty then other circuits ie. lights-on and key-in ingition alarm also rear fogs, wash wipe and front wiper delay and problems with the interior lights and window heaters.
 
discool said:
Normally the horn button earths the horn relay (passenger footwell) so it will switch a 12v to the horn terminals, you should have two horns (300 series).
Dash lights pick up their feed from the light switch.
if your MFU is faulty then other circuits ie. lights-on and key-in ingition alarm also rear fogs, wash wipe and front wiper delay and problems with the interior lights and window heaters.
Click to expand...

Getting nowhere fast, however I have just found a large relay under the passenger foot well cover, it was clipped in with all the other relays but isn't connected to anything. :confused:
 
I found the socket that connects to this Relay and it has 2 pins shorted out with a cable. Here's the relay.

Also it looks like the horn isn't standard, but it does use wires from the loom but I can't find a horn relay anywhere, and its impossible to follow the wire through the bulkhead and into the loom.
 

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The parts book gives the horn relay colour as yellow, but both dim dip and alarm sounder also as yellow.
 
discool said:
The parts book gives the horn relay colour as yellow, but both dim dip and alarm sounder also as yellow.
Click to expand...

Going on the wiring diagram I should be able to figure out which one it is by the colours of wires, but typically none of the relays have the Purple/brown or Orange or what ever it was running to them. I think I'll just rewire an earth feed straight to the horn switch and put a live direct to the horn.

I'm still completely baffled by the Hazard Warning lights though, and really need to sort this one out. I have all the wiring diagrams but a lot of the wires run to the MFU (incidentally where is the MFU?) The interior lights are partially solved, a blown bulb in the ignition barrel light was responsible, it also stopped the rear heated screen from working, as soon as I shorted it, The speedo lights and heater lights came on. I can't figure out why the interior lights flash 6 times when the door is opened though! :D I'm thinking a bad earth. :confused:
 
I see your relay PRC9666 is for the cruies control, the mfu is pluged in the the rear of the main fuse board and i would look at the indicator relay first for problems with the hazards also that the switch is fully pluged in.

The main earth connection blocks are behind each kick panel but i'm sure you have seen that.
 
discool said:
I see your relay PRC9666 is for the cruies control, the mfu is pluged in the the rear of the main fuse board and i would look at the indicator relay first for problems with the hazards also that the switch is fully pluged in.

The main earth connection blocks are behind each kick panel but i'm sure you have seen that.
Click to expand...

Thanks, I can't get the indicator rely out, in fact after releasing the little clips that hold it in, I ended up pulling the cover off it. :rolleyes: I've changed the switch over with my other Disco so have ruled that out. I'll have another play around tomorrow but I really need to solve this one.
 
No,text only for me too,assumed it was my lousy connection....try a different browser,maybe?

If the auto and manual sytems are different,maybe including looms,could someone have bodged an auto system into a manual loom?Not much point me looking at mine as they are all diesels,and the two autos have differing CC systems.The rest I bow to others greater knowledge....I am currently in recovery from an electrical problem myself.
 
I think the system is factory fitted but probably hasn't worked for years I noticed a section of Vac hose that needs replacing. I can't figure out why the relay was disconnected and 2 wires have been shorted out in the socket. I assume this was done a long time ago to bypass the relay which may have failed...?

I hate this kind of electrical fault, I'll be a lot grayer and the beer belly will have increased by the time I solve it. :)
 
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