No power on the ignition circuit

[besidethewye2]

Hi all

I got my S2 back from the garage a couple of months ago - it had gone in with the engine light showing. To cut a very long story short the garage didn't find the broken wire on the cam angle sensor but thought the issue was connected with the immobiliser/alarm and went ahead trying to take that out of the circuit.

Upshot is that when I got it back - the alarm was misbehaving and making the strangest of noises (swarm of wasps sort of noise). I turned the key switch and it stopped.

Found and fixed the cam angle sense wire break and the car appeared in good shape (ignoring the broken windscreen). It was then sitting for a week or two - nothing changed as far as I know.

BUT then it wouldn't start. I got a new battery thinking the neglected one might not have the voltage but that didn't do it. Never had symptoms like this before:

- When I turn the key nothing lights up on the dash - no warning lights, etc
- the engine cranks easily but there is nothing else
- the lights, hazard lights, radio all work
- the heater, indicators and mirrors adjustment do not

I poked around in the fuse box - there is power to the ECM fuse but no voltage showing on the ignition fuses (fuse box in the passenger footwell).

The ignition switch has power to it and when in position 2 there is power on the red/black cable.

I am not sure where to go next.

I don't know exactly what the garage did - they said they had bypassed the immobiliser/alarm but it is still there and connected clearly with power. No central locking anymore as expected.

When I took the car in the remote did work to disable the immobiliser and I saw no issue with it.

Ideally I would a) have a car that worked and b) have a working alarm/immobiliser - a) being more important in the short term of course

Any advice gratefully appreciated (no need to advise on leaving it to the garage.....)


Thanks, Patrick

[dapinky]

There is a 'complete guide to removal of the S2 Alarm system' - BUT - for obvious reasons, it is kept as a hidden file and never openly published.....

.... Jonathan Furlonger (Saltire) is the acknowledged "keeper" of the information, and should be along shortly to offer to provide it to a (verified) email address.

Should he not see this, then send me a message in a couple of days and I'll sort it out for you. (As I don't own an S2 I have never had occasion to read the info, but those who have done seem to think it is all you need to know!).

[Saltire]

There is a 'complete guide to removal of the S2 Alarm system' - BUT - for obvious reasons, it is kept as a hidden file and never openly published.....

.... Jonathan Furlonger (Saltire) is the acknowledged "keeper" of the information, and should be along shortly to offer to provide it to a (verified) email address.

Should he not see this, then send me a message in a couple of days and I'll sort it out for you. (As I don't own an S2 I have never had occasion to read the info, but those who have done seem to think it is all you need to know!).

You rang, m'lord?

Patrick: As Dave says, If you let me have an email address, I will send you a link from which you can download the OEM S2 alarm/immobiliser information. Note that it's a 7MB plus PDF file, so I don't send the whole thing as an attachment any more, as it's been known to breach some recipients' mailbox size limits.

Hope that helps!

[besidethewye2]

An update: thanks to Jonathan for the guide on the S2 alarm.

I found the main alarm control box (that's not easy to get to!) - hanging loose with just the one black wire still attached. The wiring had been modified to remove it from the circuit and I cut the alarm siren out of the circuit too.

No different.

It dawns on me that when the garage said the car wouldn't start that maybe it wasn't the alarm/immobiliser after all and it was some intermittent fault that somehow got resolved briefly and has happened again and all the effort trying to take the alarm/immobiliser out of the circuit may not have made any difference (aside from removing all the useful features of course).

I don't know where to go next - I swapped a couple of relays to see if the ignition relay might be at fault - no change.

As far as I can tell all the circuits that should switch on with the ignition are dead so, presumably, it is something near the start of that side of the wiring loom.

Any advice on where to look and what to try next would be gratefully received.

Patrick

[chrism]

Hi besidethewye2, just a thought..a prev owner wired a couple of usbs and a cig lighter into the glovebox via (I later found) the 3A VSV fuse 10 post down in the pass footwell.

Of course I used it for the mobile a few times etc but after I plugged in the EScan laptop the car wouldn't start. Can't remember if I had lights or it turned over, but I remember a feeling of extreme panic.

I traced the wire back to see it was attached to this fuse 10 post from behind the fusebox, found the fuse was blown, replaced it (3A is a bit of an odd fuse size...) and all was okay. Silly aftermarket electrics imo

I think this circuit is part of the fuel inj... reckon it's worth a check?

[KenS]

Agree with Chris, checking power from the fuses is probably the best way forward. I guess you are aware that the wiring diagrams are in the Electrical Manual that you find in the Manual section (tabs just under the Forum banner).
In there you will find:

fuses.jpg

If you have a voltmeter, checking for 12V at those fuses (on right hand side) will hopefully show a pattern which will implicate a fuse, Ignition relay or wiring. At worst it will start to eliminate some causes.
Best of luck.

[peteoddcar]

Hi
Sorry I’ve been neglecting the forum recently - I resolve to do better in 2026.
If you are still having issues I’ll try to help. If not could you post the info on what caused the failure please.
Without seeing the car it’s difficult but the fact that it has worked for a while implies it’s configured ok wiring wise. Doesn’t rule out sloppy connections though
Locate the Ignition relay remove it and bridge terminals 30/87 and see if you get any joy.

[peteoddcar]

Any updates on this I wonder?

[besidethewye2]

hi again

so sorry not to be updating the thread - Jonathan sent me useful info and I have been trying to work through things when time and weather allow (which is rarely).

While the ignition switch appears to work as expected the fuses A21,22,23 and 24 all show no voltage with ignition switch position 2.

Fuel pump A3 has power but no sign of it working

When I swap relays H and J nothing changes - the car cranks but the ignition circuits don't come on.



I wonder about pulling the main fuse box (footwell) out to have a look and check nothing has come unattached in there.

Finding it all a bit mystifying just now!

Thanks for all the input - very much appreciated.

Patrick

[peteoddcar]

Can you check with ignition on for a supply at Fuses A10 A20 - ideally with at test light probe or voltmeter into the top
Top the fuse ( the terminal tops are exposed for that reason in case you maybe didn’t know )
Report back ta!

[peteoddcar]

Can you check with ignition on for a supply at Fuses A10 A20 - ideally with at test light probe or voltmeter into the top
Top the fuse ( the terminal tops are exposed for that reason in case you maybe didn’t know )
Report back ta!

[besidethewye2]

@peteoddcar - I checked both A10 and A20 - nothing on either - 0V.

The brass receptacle for the fuse on A10 (lower - output I think) is broken - another reason I want to get behind the fuse box.

The only other thing that could possibly be relevant - when I got the car back I was having the maddening noise (like a swarm of angry bees) from the alarm siren until I turned the key switch off. It did run and start after that but I suppose the internal battery in the siren would have run down perhaps over time after that. The control box for the alarm has been removed (by the garage) from the circuit leaving only the black wire attached. The siren has the one plug still in (and the other purple wires for the fuel pump out and cables linked).

The red/green wires that went to the control unit and are now linked show no voltage in any ignition position (the other wires that feed the starter motor circuit show voltage as expected.

No more light or energy now.

Thanks again

[peteoddcar]

Good info
I think you need to check for a supply on the thick black wire from the ignition switch, and that it is connected to the thick white to the wiring harness. Its possible the male blade has pushed back in the connector so not making contact, but it was.
Its located around the bottom of the steering column shroud.
For the fuses to be all 0v its probably an issue with this circuit or the switch itself.

[peteoddcar]

If you need a new terminal for the fuse box or the ignition switch inline connector, PM me, I have some I can spare.

[besidethewye2]

@peteoddcar - thanks - sorry, I have been away.

Let me check those and get back to you - thanks for the kind offer.

[besidethewye2]

@peteoddcar

so I finally got back in the car

There is definitely power as there should be on the ignition switch and the outputs from there. But the white cable at the fuse box end has none.

I am struggling now to get to the connector from the ignition switch to the wiring harness - it looks ok but I simply can't reach it. So I am in the process of getting the dash off - stumped at present with removing the steering wheel - I will get back to that, hopefully in the morning.

Do you know if the group of cables that includes the white ignition switched line goes into the engine bay or stays under the dash?

I have done about enough of the lying on my back sliding in under the steering wheel and trying to reach up under the dash......

[peteoddcar]

Hmm
You’ve got the shroud off ? Not that bad to get too I didn’t think
Disconnect the battery first
Drop the ignition switch from the lock assy, two small grub screws and if I recall correctly you should be able to feed the whole lot into the foot well to expose the connector
Not done it for a while but I think that’s the method
Really shouldn’t need to take the dash off, thats major

[besidethewye2]

Thank you - sounds far more sensible than me trying just to reach it. I am out of practice clearly and thinking slowly! Let me see and report back.

[besidethewye2]

@peteoddcar got the ignition switch connector out and, as you suspected, he one connection was pushed out and not working. Pushed it back in and the ignition circuits are live again. The starter won't crank so I need to go back and make sure that connection hasn't misbehaved......slowly slowly getting there. Thanks for the help.

[peteoddcar]

Seems like your garage really messed up your car’s wiring. The lack of crank. Try to bridge the start relay pins 30 and 87 that will at least tell you if it’s up or down stream of the relay ( if it cranks it’s up stream )