No ignition light working on series 1 1/2 etype

[johnj]

My series 1 1/2 etype has ignition light problem when i put the dash top on a couple of lights on speedo came adrift when i re attached them the ignition light wont come on ,swapped a bulb with one that works and original one was also fine, no fuses out all wires look ok and its a new loom car starts fine but no ignition light on dash ??
Any idears cheers John

[mark10337]

I have sometimes found the same when replacing the lights. The light grounds through the bulb holder, and I noticed sometimes it wasn't quite clipped in correctly, or some of the pins have bent preventing a good earth. They can be a devil of a job.

[johnj]

Lights clipped in but no ignition light illumination car starts fine

[mark10337]

My mistake, that bulb gets grounded through the 3AW.

Do you have +12v on the white wire. This comes from fuse 6. Probably goes to the centre pin on the bulb holder.
If not, trace the white wire back to fuse 6, it should go directly.

Next, the bulb is operated via grounding provided by the 3AW unit. Is the ground wire (black) on the 3AL attached to ground. ie. do you have connectivity to ground on terminal E with the wire connected?

Connection AL (Brown-Yellow) goes to the alternator AL. If you apply 12v to the AL terminal on the 3AW, you should get ground connectivity on the WL terminal on the 3AW. If not, the 3AW is probably faulty but can be tested as following.

Using an ohmmeter, test the resistance between the AL lead and the E lead. This should be 16-20 ohms. Anything outside of that range indicates a bad relay. If there's no conductivity between AL and E, the relay is defective.

Measure the resistance between WL and E. This should be close to zero. If it's more than a couple of ohms, replace the relay.

When switching the ignition on, but not starting the car, do you have +12v at the alternator AL terminal (brown-yellow)? If not, the alternator seems to be the fault.

[johnj]

Hi thanks for the reply but not sure what you mean about 3aw
also what do you mean by A L lead and E lead whats terminal E
Whats W L & E
Im not very electric minded thanks for the help

Regards John

[johnj]

Anyone can answer above questions

Thanks John

[mgcjag]

Hi John.....i dont think you can get more detailed help than Mark has given above......do you have a Jaguar service manual and a wireing diagram......they are in the Knowledge base section.......the 3aw is the ignition warning light module..a small tin can shaped unit located under the heater.....E, AL, WL are its 3 terminals...how it works is explanied in the manual.... Steve

[christopher storey]

I cannot say if this would apply to your car, but on quite a lot of S1 4.2 cars , the ignition light was nothing to do with the alternator at all, but was driven off a an oil pressure light switch plugged into the long gallery which runs the length of the block on the right hand side at oil filter level ! Don't ask me why???

[mark10337]

Hi John

Sorry for the delay in replying again. I suggest you look at the wiring diagram for the Series 1.5. It is in the knowledge base section as Steve mentioned. Look at the diagram, find the alternator / 3AW / ignition warning light / wire to Fuse 6. Then trace along it using the guidance I gave above. It should become apparent. If not and you don't feel comfortable testing the electrics, I suggest you find a car electrician or someone local who can take you through it. It's fairly basic electrics.

[johnj]

Thanks Mark & steve I will have a look at it this weekend,
ive got a workshop manual so hopefully with your input we can get it sorted

Much appreciated, love this site very helpfull people out there "

[johnj]

Big thanks to Mark and Steve on info regarding the ignition light problem
After going through the tests they suggested, we did find the problem was with the 3AW relay so we have ordered a new one
Thanks guys for all you excellent advice,
now on with the build

Best regards

John

[Durango2k]

Do not throw the old one away. I would open it and have a look inside. Its very simple and a kind of a heater element. Have a look, they can be repaired, and I am not sure wether I would trust a repro more then a mended part from „the midlands“, as Clarkson used to say...

Carsten