borg warner 35 inhibitor switch

[Lemp1953]

Hi all,
My Inhibitor switch is playing up and might need to replace it. Can anyone instruct me on its removal please and is it the circular type.?
Mike

[Goldstar]

Looks quite well documented in the ROM and easy enough as long as the exhaust plays nicely. Not done it myself though I have to admit.

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[MandM]

Check all the connections and clean the big connector first, the switch does adjust see above rom

[marshman]

If it is a BW 35 box then your car should have a small "inspection" cover plate in the passenger side of the transmission tunnel. Undo the screws and you can see the switch. It is a bit of a fiddle but you can get to the wires and check them first (also check the multi connector further along the loom as suggested by MandM - need to do that from below the car). You can then also check the adjustment - documented in the R.O.M. or if all else fails remove and replace it. No need to get under the car and struggle with exhausts etc. !

[Lemp1953]

Thanks guys, I'll look in the rom and remove the inspection cover and spray some electrical cleaner there as well.
Mike

[marshman]

The switch is effectively sealed so the cleaner probably won't do a lot. Pull the wires - there are four, two for the reversing lamps and two for the starter inhibitor, so don't mix them up. Pull them all off and push them back on again, check they are a nice tight fit, if they are loose just squeeze them up a tad with a pair of pliers. Worthe finding the connector and pulling it apart, and checking the pins are clean, give that a spray with cleaner before plugging back together.

[MandM]

It's this big plug block above the exhaust, you should be able to reach easily underneath

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[DJT]

It's this big plug block above the exhaust, you should be able to reach easily underneath

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Having taken this apart a couple of times to clean it, mine was looking a bit rough after 50 years. I removed the plug, and replaced it with bullet connectors sealed with heat shrink tubing - the type with glue inside. It will not need taking apart again. Not original, but who looks under there apart from me and my MOT tester?

[jbuckl]

Having taken this apart a couple of times to clean it, mine was looking a bit rough after 50 years. I removed the plug, and replaced it with bullet connectors sealed with heat shrink tubing - the type with glue inside. It will not need taking apart again. Not original, but who looks under there apart from me and my MOT tester?

There’s usually some corrosion in that connector , often the root cause of trouble…. Sometimes the switch itself is fairly, sometimes needs adjustment.

[APS]

I recently had a no start issue. Thought it might be the inhibitor switch, especially seeing how I had recently been under the car a few times dealing with a gearbox leak. Maybe I disturbed it. So I done a search on this forum and found mention of this connector being a possible cause for non start. So before pulling out the jack and axle stands I gave that connector a good waggle from above. Low and behold the car started and has been ok for the past week. Now on my list to get back under the car to give that connector a good clean up.

[wilf]

When I took that connector apart (chasing what I thought was an inhibitor switch problem) I wondered how any current at all had managed to flow through the mess of corroded bits that I found!

[Lemp1953]

Thanks, that's all good advice,
Mike

[Roger M]

The switch is effectively sealed so the cleaner probably won't do a lot. (...) Worth finding the connector and pulling it apart, and checking the pins are clean, give that a spray with cleaner before plugging back together.

Thanks: what a revelation! I recently had to buy a new inhibitor switch for my BW35. Looking at it in the packet, I had no idea that I could (literally?) have pulled it apart.

I have now had the luxury of an expert to fit the new switch for me. (How happy I was that the inspection panel allowed him to sidestep all that horrendous workshop manual guidance!).

In the wash-up, it seems that the old nearly new Lucas switch had failed in use when the plastic section started to push itself out of the metal body. In effect, this withdrew its plunger from the actuating mechanism - but luckily not so far as to prevent me starting the engine - just as long as I did so in 1st gear (!). Food for thought.

[jbuckl]

Good info here