HU Won't Stay On. Igniton Switch Issue?

[Conker]

I fitted a new headunit today into my 1991 Mk2. All was going well - after connecting everything the HU powered up nicely once I put the key in (no key turn required, just slide the key in). This was how the previous HU worked as well.

Then, I moved the HU a few inches to a slightly different place on the dash and it suddenly went off and couldn't be turned on again.

After a lot of fiddling I found that if I push the key into the ignition as far as it will go and hold it there, the head unit comes on again but only as long as I hold the key in. I've searched the forum and apparently this might be the ignition switch, but my questions are...

1) All other elctrics are fine. How can I check the ignition switch is at fault?

2) Was it purely coincidence, or could the ignition switch have suddenly broken because of what i was doing, e.g. a short (the wires were still all over the place)?

3) Should I just bridge the yellow and red wires together to make a permanent live?


Thanks.

[Mikester]

Permant live is up to you, if you can live with that. But i had this issue with the stereo not comin on, and not starting.

When you turn the key all the way before ignition, is it stiff and tight as it should be to start when u twist it further?

If not, its the switch......

Cost me £127 with labour and VAT to get a new one fitted in my MK3.

[Conker]

The "starter turn" bit is still nice and tight. There is no problems starting the car either.

[Mikester]

Hmmmmmm maybe its not the switch then. I would think its a loose connection. Athough its strange it stays on with the key. But it starts fine and tight....... :/

Stumped.

[Conker]

Stumped.

Me too!   

I'm going to get my voltmeter out tomorrow and have a closer look.

[russ-vdub]

yeh dvm (digital voltmeter) all the way.. electrics is simple when you know how. may need the haynes to make sure dont short anything but i personally would just wire the hu up to permenant live. saves messing with wires on the ignition coil and removing dash trim etc etc

[tobz.]

The stereo switch on the ignition is just part of the white electrical switch that is plugged into the end of the ignition barrel. Cheap to buy and less than 30mins to fit. If it was getting a bit tired anyway and you managed to short some wires then you could have finished it off. E.g. the contacts were a bit dirty, you passed lots of current through them causing an arc, this arc burnt the cr@p on the contacts and now they need constant pressure (from the key) so remain connected.
Get down the breakers or on ebay or stealership and get a new white switch housing.

[Mikester]

£18 from Vdub.

[Conker]

Cheers guys.

In the end I went down the permanent live route - It was the ignition switch that was at fault.

[Mikester]

The stereo switch on the ignition is just part of the white electrical switch that is plugged into the end of the ignition barrel. Cheap to buy and less than 30mins to fit. If it was getting a bit tired anyway and you managed to short some wires then you could have finished it off. E.g. the contacts were a bit dirty, you passed lots of current through them causing an arc, this arc burnt the cr@p on the contacts and now they need constant pressure (from the key) so remain connected.
Get down the breakers or on ebay or stealership and get a new white switch housing.

£128 to buy, labour, and VAT on my MK3 Gti for a switch!!! Switch was only £18, £90 labour.

Stupid mk3!