Inhibitor Switch

P

prospect8816

Member
Hello one & all. This is my first time on the Forum, so please bear with me. I own a P6B series 2 1974/5 3500 v8 auto. I am having a problem starting the car in PARK. It starts ok in NEUTRAL but not in PARK. Is the fault with the "Inhibitor Switch" or (as has been suggested by non-members) an adjustment problem? I would appreciate members thoughts on this, thank you. :?
 
Hello prospect8816,

Welcome to the forum.. :)

I would say the most likely cause is indeed the inhibitor switch. I had the same problem, would start in NEUTRAL but not in PARK. It did this for more than 20 years as i was not overly bothered by it, but each time I had the transmission rebuilt I asked if they could sort the problem, but all to no avail. So when my engine was replaced with the 4.6 I asked if a new inhibitor switch could be fitted at the same time,...it was and the problem was no more.. :D

Ron.
 
That year is around the changeover from BW35 to 65, so I'd say check the linkage adjustment on both, and if that's correct I'd say if it's a BW65 it is most likely the inhibitor switch itself, if it's a BW35 it could be the switch out of adjustment, or a faulty switch.

Best way is use a test lamp/continuity tester on the inhibitor switch connections, and it will light up in NEUTRAL, then try PARK and see if it comes on if you move the selector lever on the box slightly.

It would help to know which type of box it is, my guess would be 65.
 
To: harveyp6. Thank you for the info, and yes it is the "BW65 auto type gearbox". Since I don't have the items you list to test, I assume it's one for the classic car mechanic to sort & rectify?

I have been in touch with Chris York who recommends I get in touch with "Harvey Lowther", is "harveyp6" you??
 
prospect8816 said:
I have been in touch with Chris York who recommends I get in touch with "Harvey Lowther", is "harveyp6" you??
Click to expand...

The very same!

You could do without a test lamp or contunuity tester, just use a bulb in a holder and a couple of wires and a slave battery.
All of that assumes you have the ability to get under the car in the first place.
 
To: Harveyp6. In answer to your question " Where are you"? I live in West Sussex near the town of Worthing. Also i answer to the name of: Paul.
 
Again to Harveyp6. I used to have all these items when I used to work on my cars, and more besides, but when I gave up owning/driving older cars, I either gave away or "filed" those items. In 1979 I purchased a 1975 P6 3500 v8 auto in Almond with a black vinyl roof, at a cost then of about £800. My present car in Mexico Brown cost me £900! That's inflation for you!! Now my main car, is a 2003 Honda Civic 1.6 Exec Automatic. Goes very well and so it should, but I wouldn't know where to start if I had to do my own maintenance.....!
I do own a trolley jack & I could borrow a pair of axle stands, so getting under the vehicle wouldn't be a problem, I hope!

Also Harvey, (may I call you Harvey?) is the failure of the reversing lights coming on when selected, due also to the inhibitor switch?
Paul.
 
prospect8816 said:
Also Harvey, (may I call you Harvey?) is the failure of the reversing lights coming on when selected, due also to the inhibitor switch?
Paul.
Click to expand...

Both the starter circuit and the reverse lights are run through the inhibitor switch, so it's possible that the switch is faulty on the reverse lights as well, or there's another problem. You really need to check out the switch and the adjustment of the selector cable as a first stop, you may find the switch loose on the box, but then if you find the switch is faulty on either the reverse lamp or starter circuit it can be replaced, if not you'll need to start looking elsewhere. If it needs a switch they are still available.
 
prospect8816 said:
To: Harveyp6. In answer to your question " Where are you"? I live in West Sussex near the town of Worthing. Also i answer to the name of: Paul.
Click to expand...

Not exactly local to Essex, but if you ever get to the point where you thought the trip would be worthwhile I'm sure we could organise something to sort things out for you.
 
To: Harveyp6.
Harvey, As promised the results of yesterdays examination of the inhibitor switch. Firstly my mechanic friend forgot to bring the ramps to run the car up on, so all he could do, was move the gear selector forward & back several times fast with the engine switched off, and then try to start the car in Park. This he succeeded in doing, so he repeated this procedure again & again, and 7 out of 10 times, the car started up. He also started the car in Neutral in the process, and the car started first time each time. However, he did find that he had to hold the gear selector hard forward when in Park to start, meaning that maybe the gear linkage is perhaps a bit worn?

I think I can live with that. Just so long as it starts.......

Thank you for all your help

Paul
 
prospect8816 said:
However, he did find that he had to hold the gear selector hard forward when in Park to start, meaning that maybe the gear linkage is perhaps a bit worn?

Paul
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With the 65 box the linkage being a cable is less likely to go out of adjustment, but a build up of very slight wear in the lever itself coupled with a fraction of stretch or wear in the cable can put it out just enough that you have to lean on the lever to get it to start in PARK. The locknuts on the cable can also come loose causing the same thing, but just resetting to allow for this should get it working perfectly again.
 
prospect8816 said:
To: Harveyp6.
Harvey, As promised the results of yesterdays examination of the inhibitor switch. Firstly my mechanic friend forgot to bring the ramps to run the car up on, so all he could do, was move the gear selector forward & back several times fast with the engine switched off, and then try to start the car in Park. This he succeeded in doing, so he repeated this procedure again & again, and 7 out of 10 times, the car started up. He also started the car in Neutral in the process, and the car started first time each time. However, he did find that he had to hold the gear selector hard forward when in Park to start, meaning that maybe the gear linkage is perhaps a bit worn?

I think I can live with that. Just so long as it starts.......

Thank you for all your help

Paul
Click to expand...

My BW 35 has been like that for at least 20 if not 25 years. Occassionally starts in park or neutral but usually not in park unless the lever is pushed right forward and not always when that is done. Must be a common problem. I have lived with it for ,as I said, at least 20 years!

Cheers

Tony Bunting
 
ajcb said:
My BW 35 has been like that for at least 20 if not 25 years. Occassionally starts in park or neutral but usually not in park unless the lever is pushed right forward and not always when that is done. Must be a common problem. I have lived with it for ,as I said, at least 20 years!
Click to expand...

It doesn't have to be that way............
 
It's all about priorities!

1 Day (x) and night (y) = 24;

y-x = 6 = unhappiness;

y-x = 8 = happiness

Cheers

Tony Bunting
 
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