Handbrake light

[Guest]

Hi all, while driving my handbrake light comes on and off, i have traced the fault to the 5way joint on the inner wing. The switch connection has brake fluid in it! So, do i need a new 5 way thingy or just a new switch?? What does this joint do anyway?

Thanks

Jason

[seaside bill]

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Jason



That'll be the Pressure Differential Warning Actuator, otherwsie known as the PDWA switch. Its purpose is to warn ofunequalpressures between the front and rear braking circuitswhich is indicative of a fault in one of the hydraulic circuits e.g.one has sprung a leak - suggest you thoroughly check out your braking system.

[Guest]

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Oh, right, better do that then, thanks.

Jason

[aerosilver]

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Mine comes on now and again, particularly if I haven't driven the car for a week or so- I think thesensor can get a bit over-sensitive, as once I've driven it for a while and given the middle pedal a few stamps it goes out and stays out, so as long as your hydraulics look OK and the fluid level is normal I wouldn't worry too much.

Bob.

[DJT]

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Jason,

Are you sure the fault lies with this switch? This PDWA switch contains a shuttle valve that moves one way or another if pressure is lost in either the front or rear hydraulic systems. This then illuminates the red light on the dashboard between the speedometer and rev counter. I don't think it has any connection to the handbrake warning light, which is in the warning cluster.

The red light comes on dim when you turn on the ignition to prove the bulb works, then goes out when the engine starts as it is wired in series with the oil pressure switch.

The handbrake warning light is activatedby a switch at the handbrake lever, under the carpet.

If the PDWA light is coming on, it is possible to remove the switch from the PDWA and centralise the shuttle with asmall screwdriver. The shuttle is basically a steel rod with an o-ring at each end and a 'waist' in the middle that the plunger for the switch sits in. If the shuttle is displaced the 'waist' section moves off centre and the plunger is pushed in, operating the switch.

Dave

[seaside bill]

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Dave

I think I read somewhere that there's a difference between the Mk1 and Mk2 PDWA setup. Early cars used the oil pressure light and Mk2s the brake warning light as the test bulb.

[DJT]

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seaside bill wrote:

Dave

I think I read somewhere that there's a difference between the Mk1 and Mk2 PDWA setup. Early cars used the oil pressure light and Mk2s the brake warning light as the test bulb.

Ah! Perhaps you are right. I am a long way away from my ROM at present, so can only speak from Mk1 experience.

As usual, always prepared to learn.

Dave