Seat belt warning harness

[secondtimer]

Time to resurrect an old topic. My 99.9% completed Sprint suddenly at the last hurdle has decided to start playing silly buggers on me. Seat Belt warning light won't function and I get an intermittent 'Brake' light staying on in the multi display.

I have two leads that exit on the passenger side under the seat, Light Green & Orange and Light Green & Green - all good so far and matches the wiring diagram. But just a single black cable exiting the seat. Could someone have a look at a working one for me and tell me if that's right and I just 'plug it in' or am I a lead adrift there?

Its been over 14 years since I took it all to bits - my memory just aint that gr8!

I checked the handbrake connection and that's all fine so presume its something to do with the union and connector under the bonnet for the brake - is there anything else to check as they're not overcomplicated are they?

[Jon Tilson]

If you have a brake circuit imbalance the light stays on. You can reset the shuttle switch on the multi way pipe connector on the dashboard.

If the pedal is spongey maybe the light is doing its job.

Jonners

[MIG Wielder]

I suspect 2 separate faults here.
I'll try & describe them in 2 parts.
1. The seat belt light problem. I think the first thing to do is eliminate the possibility of a dead bulb or wiring. With the ignition on ( for a short time only, connect the Light-Green / Orange wire with a piece of extension wire to a good earth. The seat-belt light should illuminate. If not check the bulb and its wiring down to the seat.
Now the seat-belt light has 2 separate paths to light it. One is by the Driver's seat-belt switch; the other is by the passenger side seat sensor switch and the passenger side seat-belt switch.
The driver's side is easier to sort first in this situation.
Peel back the carpet by the drivers side seat belt stalk. There should be 2 wires going inside it. One goes to Light green / orange. The other is black -earth. Again connect the Light green / Orange wire to a good earth with the ignition on. The Seat-belt light should illuminate. If not, the problem is in the Light Green / Orange wire. If there is still a problem then it is in the black earth wire or the switch in the seat belt stalk itself or the push-connectors.
At this stage when the seat-belt light is on, plug the drivers side seat-belt in. The light should go off. Sorted for the driver's side!
Let us know how you get on at this stage and we can then de-bug the passenger side. As a matter of interest I can't think why there would be a black ( earth ) wire going to the passenger side seat-switch. Can you see where else this goes please ?
It isn't black-with-a-white tracer is it ? That is the one that should go to the switch at the base of the handbrake lever. Are the wires crossed over here somewhere ?
I read Jonners post with interest . Is the car the nice blue one in the User Avatar ? If so does a "T" reg car have dual circuit brakes and the PDWA ?

[Carledo]

My T reg Sprint auto VA 26140 Reg 1/8/78, the first day of the T plate, has only single circuit brakes. However I think the change came somewhere in 79 so it COULD have dual circuit brakes on a T.

Steve

[AlanH]

You can reset the shuttle switch on the multi way pipe connector

How do you reset this.

[RobCavendish]

You can reset the shuttle valve by careful use of a jeweller's screwdriver (or similar) on the shuttle of the PDWA unit once the electrical connection and switch have been removed from the centre of the unit, this is located on the driver's side of the bulkhead. Of course, this will only work if the brake balance is correct, typically no fluid leaks or air is present.

[secondtimer]

A bit late in the day on this but 'finally' sorted all the seatbelt/brake warning light issues.
You were right Mig Welder - one of the passenger seat squab leads had completely pulled out and then gone astray in the rebuild, so was missing. Just soldered in a new fly-lead and done. The brake lamp on the dash flicks on now and again but with no leaks and all the front brakes now brand-new I am sure its the PDWA that's gunged up and sticking, so that's the next job!
Thanks all.

[markas]

I had a brake warning light that flickered on and off many years ago on a Dolly 1500 that was only a couple of years old. Turned out that the wiring in the engine bay was resting on the engine block. The insulation melted, and it shorted out intermittently onto the block, causing the light to come on. A simple fix to patch the wire with insulating tape and reroute it!
Glad it was nothing more technical, as it would have had me stumped