MG Midget Forum

After 25 years of my PDWA not working, I decided to put it right. I rebuilt the 4 pin cockpit switch and bought a new PDWA switch (AAU2454) from one of the big British parts suppliers. Just for fun I bench tested the switch. Both contacts on the harness side were shorted, so that checked out. No continuity between the extended plunger and the other two contacts, that's good. And when I pushed in the plunger - nothing. No beep. No continuity between the plunger and the two contacts that interface with the harness. I expect that when the shuttlecock translates and pushes up the plunger, it should provide an electrical contact between the grounded master cylinder and the two harness contacts.

Now a guy could be forgiven for buying a new AAU2454 switch, installing it in the master cylinder, jumping into the cockpit, pushing little rocker switch, see the little red light illuminate and claiming victory. Safe in the knowledge that whatever margin of safety is afforded by the PDWA is good to go. But it's not. Becuase a failed AAU2454 switch can still test good-to-go from the cockpit.

I called the British parts supplier and they have shipped out a new one. They will remain unnamed as they have been great in the past, and anybody can make a mistake. I will say that explaining the problem to them was not a joy, and I'm not convinced they have a grasp on this. Well, the replacement part should shed some light on whether this is a systemic failure or an isolated case.

My suggestion to my MG brothers is to not trust in a new part, especially a safety part when it only takes a minute to test it on the bench top.

Good idea to check first!

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Iceman

Atlanta GA

71 MG Midget

62 AH MKII
67 Midget
71 Midget