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PDWA switch?

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Driven76

Senior Member
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Hi Guys,

I ordered up a new PDWA switch from VB to replace the one that went bad on my '76 TR6.

Unfortunately, the one they show as fitting my car does not fit and they say it's the only one they carry.

I guess I could do without one since it appears the switch only controls the light on my dash, and I figure I will know something is up with my brakes without a light telling me so. But I would like to get a replacement if possible.

Any one know where I can get a correct replacement?

I have been watching eBay for a few weeks for either used or NOS, but haven't had any luck yet.

Thanks,
Roger
 
DNK said:
What happen to the old one?
Click to expand...

I'm not sure, just assuming it's bad. It's still in place, just not connected.

My light came on a while back, even though I didn't feel anything was wrong with the brakes.

When I checked things out, the right rear was hanging up a bit. After adjusting everything seems fine with no leaks.

I have logged over 400 miles since with no brake issues... but the light still remained on.

Roger
 
If the wiring is off on the Oil Pressure Switch, you can have brake light problems.
 
Driven76 said:
My light came on a while back, even though I didn't feel anything was wrong with the brakes.
Click to expand...
You may also want to check your handbrake switch. I believe it also activates the brake warning light on your TR.

Its a very simple contact switch, and it goes 'off' by dropping into a recess in the handbrake lever when you take the brake off, and sometimes it just sticks or it twists on it's mounting and the contact arm doesn't drop. The symptom is your brake light stays on.
 
What they probably sent you was for a Spitfire or even a Jag. It will work, just need to bend your pipes a bit.
 
If your PDWA switch isn't leaking, I agree with Andy and think you should at least try a brake bleed first. You could just have the shuttle not centered and it may be reset with bleeding pretty easily.

Randy
65 TR4
 
guzzul said:
[You may also want to check your handbrake switch. I believe it also activates the brake warning light on your TR.

Its a very simple contact switch, and it goes 'off' by dropping into a recess in the handbrake lever when you take the brake off, and sometimes it just sticks or it twists on it's mounting and the contact arm doesn't drop. The symptom is your brake light stays on.
Click to expand...

We have a Handbrake switch??? /bcforum/images/%%GRAEMLIN_URL%%/confused.gif
 
Driven76 said:
Unfortunately, the one they show as fitting my car does not fit and they say it's the only one they carry.
Click to expand...
Stupid question : In what way doesn't it fit ? Wrong threads ? Wrong electrical connector ?

And while nothing is impossible, I think it's unlikely that your old switch failed "on" for no reason. More likely, as others have suggested, the PDWA shuttle moved for whatever reason and activated the switch.

Although I've not demonstrated it yet, I have a suspicion that even relatively minor faults, like the rear brakes being out of adjustment or spirited driving causing repeated pad knock-back, can cause the PDWA to activate. At any rate, you certainly would not be the first to have the light come on for no apparent reason.
 
DNK said:
We have a Handbrake switch??? /bcforum/images/%%GRAEMLIN_URL%%/confused.gif
Click to expand...
Varies by model & year. A 78 Spit does, and Stags do, but I think only 76 TR6 does while earlier TR6 don't.

Are we confused yet ?
 
DNK said:
What about my 8?
Click to expand...
Sorry, I don't have information for the TR8. Looks like the TR7 did from at least 76 onwards though, so there's a good chance your 8 does.
 
Sorry, not sure about an 8, but as Randall says I would expect it would. Maybe not wired the same though.

For those equipped with the handbrake switch, you should be able to test whether the PDWA switch is causing the light-on problem by just unplugging the connector at the PDWA. The light should go off, because it is the switch that provides the ground.

If the light doesn't go off, it may well be that the handbrake switch is permanently grounded. (Ask me how I know)
 
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