IGNITION SWITCH PROBLEM

[p5andrew]

I have a P5B which has the later type ignition switch on the steering column.  All had been working OK i.e. first position and the warning lights and so forth powered up, turn to next position and the engine turned over.  Turning back one click gave the accessory position. 


Returned to the car the next day to discover things had changed; turning to first position gave me warning lights as usual but when turning to the second position so start her up the warning lights went out and the engine did not turn over.  Turning the key back to the accessory position brought all the warning lights up exactly as at first position.  I am fairly adept at electrics and could no doubt eventually sort this but if anyone on here can give me a few pointers as to where to look it might well save me some time and effort  and I would be very grateful!

[westoz]

Dirty earth terminal on battery or where lead bolts to body? Low draw will light up the dash, heavy draw will rob all power.

[djm16]

The most important cause to exclude is a short-circuit. So use an ammeter in line with the battery and try again. Then, I agree, a poor earth at the battery might also cause this.

[ray]

Andrew, I too had trouble with this switch. This has the armoured cable to the coil, so I didn't want to cut it. Mine would not operate the starter unless I "giggled" it. I loosened the switch from the column, after removing the covers and tipping it over I sprayed WD40 into it and operated it a few times, tipping it forward and backward. Since then it has operated perfectly. Mine has always shown the ignition lights when in the auxilarry position.

[lagain]

Flat battery ?

I had a problem with mine, just one of the wires had been trapped in the steering column and with the movement of the steering wheel the wire broke, so would only work when the steering wheel was turned. Very unlikely, but try wiggling the steering wheel with the key turned.

[p5andrew]

Very many thanks to all of you for your suggestions.

I did wonder about a flat battery or earthing problem.  I therefore connected up our starter pack (fully charged!) but when I tried the key the fault was unchanged.  I then disconnected the starter solenoid lead, connected up a flying lead to the solenoid and when connected to a +ve feed (unfused side of the ignition control fuse where there is a spare terminal) the start motor operated as it should.  This would seem to discount battery and/or earthing problems.  The possibility of a short circuit somewhere must still be a possibility so I will test for that next.  If that does not show up any problems I will try WD40 to the switch as Ray suggests.  I will get there in the end!

[ray]

Well, you are following logical steps. Do let us know what fixes it. Regards. Ray

[johnwp5bcoupe]

Feb 25, 2020 19:44:48 GMT p5andrew said:

Very many thanks to all of you for your suggestions.

I did wonder about a flat battery or earthing problem.  I therefore connected up our starter pack (fully charged!) but when I tried the key the fault was unchanged.  I then disconnected the starter solenoid lead, connected up a flying lead to the solenoid and when connected to a +ve feed (unfused side of the ignition control fuse where there is a spare terminal) the start motor operated as it should.  This would seem to discount battery and/or earthing problems.  The possibility of a short circuit somewhere must still be a possibility so I will test for that next.  If that does not show up any problems I will try WD40 to the switch as Ray suggests.  I will get there in the end!

You wont have a short Andrew otherwise you would have a blown fuse or "smoke" it could still be the switch sc between the aux and start?

Trying to read between the lines!! is the start relay energising? is the inhibiter switch working? volts on the W&R to the Inhibiter switch? permanent volts on the thick Brown on the Relay? volts on the W&Bn when/if the relay energises?

[djm16]

"You wont have a short Andrew otherwise you would have a blown fuse or "smoke""

The reverse may be true, but I would not rely on the absence of smoke or blown fuse to determine the absence of a short-circuit. It depends where it is, and whether that circuit is fused.

[p5andrew]

Many thanks all for your suggestions.  In the event the fault was due to a break in one of the wires to the inhibitor switch.  Why it decided to fail overnight is anyone's guess!  

Now on to the next job...

Andrew

[Phil Nottingham]

Thanks for the update as it really helps others - Wild cards remain persistent!

[tonys]

I agree with Phil on this (updates). Not necessarily this forum but I've seen many where people seek advice/guidance/ideas, presumably they eventually often sort out their problem but never spend two minutes to update their thread which would, of course, then potentially help others in a similar position.

I'm glad you managed to sort it out eventually.

[johnwp5bcoupe]

Glad you got there in the end Andrew your fault was in the "sods law" category

[dmaxwell]

I'm sorry but I have to ask, what is "Sods Law"? I'm assuming that is something like Murphy's Law (whatever can go wrong will go wrong) on my side of the Pond?

David, California

[johnwp5bcoupe]

Mar 9, 2020 18:35:17 GMT dmaxwell said:

I'm sorry but I have to ask, what is "Sods Law"? I'm assuming that is something like Murphy's Law (whatever can go wrong will go wrong) on my side of the Pond?

David, California

That will do David as well as Sh 1-t happens

[djm16]

Sod's law goes something like this:

Buttered toast always hits the floor butter side down, unless you are trying to demonstrate Sod's Law, in which case it lands butter side up.

[OlafR]

Fun fact: in Germany Murphy's law is widely known (at least among English speaking folks), but hardly any poor sod has ever heard of Sod's law.

[dmaxwell]

Of course there is O'Toole's corollary to Murphy's Law that states that Murphy was an optimist!