engine will not turn off.....only when hittting the brake

[lars1965]

Had problem with my brake light , so I changed the brake switch and tried lot of bulb and tried reverse wires etc…… finally same strong brake light in both rear light when hitting the peal with ignition on.

BUT today starting the engine , the engine can not be turned off with the key… BUT if I hit the brake when i had turned the key of , THE engine shuts down!!!!
so engine can only be shut down if I hit the brake when turning the Key!!!

almost start hateing the car….

what is going on,? the only thing I did was change the brake light switch , new bulbs, cleaning bulb connectors, grounds etc. and had never had any of those issues

thanks

Lars

[304065]

Lars, something's wrong with your wiring, big time. post up some clear digital photos of the fuse box up front, the back of the ignition switch and the wires behind the gauges, and we can sort it out. Take a couple from different angles.

[Frank Beck]

Back feeding through alternator.
First rule: Unwind everything you've done one step at a time. Start with brake light switch.
I suspect you've re-installed one of your bulb holder wires incorrectly.

[lars1965]

No wires connected wrong for sure , been very carefull and have cleaned/checked all


I forgot to say that the old switch was very bad , and in bad condition, (perhaps shortcutting) as the rearlight always was glowing very litte , even though the light switch was of.
and that I also this year have fitted CDI from parts classic , have read that some swb owners + others with msd/CDI have had the same expirence that engine not will turn of, only way to shut down , by hitting the brake, They fitted a inline diode 100v/1a on the wire to the altornator bulb under the dashboard

I will try to take out the bulb to se ....

thanks

Lars

[Jim Breazeale]

No wires connected wrong for sure , been very carefull and have cleaned/checked all


I forgot to say that the old switch was very bad , and in bad condition, (perhaps shortcutting) as the rearlight always was glowing very litte , even though the light switch was of.
and that I also this year have fitted CDI from parts classic , have read that some swb owners + others with msd/CDI have had the same expirence that engine not will turn of, only way to shut down , by hitting the brake, They fitted a inline diode 100v/1a on the wire to the altornator bulb under the dashboard

I will try to take out the bulb to se ....

thanks

Lars

Frank has hit your problem on the head. Your alternator is still energized and still putting out voltage, even though, the ignition is turned off. You have a wiring issue and it won't go away until your wiring is fixed and not by fitting a diode, either!

Regards

Jim

[lars1965]

Thanks for all the input, I will post pictures to John.

My own opinion is that I think that it is the new cdi causing the problem, It did work up to now maby because the bad brake switch shortcut pulling the power when engine shut down. Have changed nothing besides brake switch.
All is checked and cleaned , I mean ALL , bulb, cornector, grounds, wires checked/reversed and checked again
I have just been though all this getting my hazard flasher /relay working ( thanks John :-) It works great now , with or without engine running.
apperently it is somehow a common problem, search 100v/1a diode msd porsche

I will get the diode jus in case

Lars

[lars1965]

The 100V/1A diode did the job....... now to find out why.

[Jonny Retrofit]

The 100V/1A diode did the job....... now to find out why.

Dear oh dear, design fail.

[lars1965]

please explain ?

[Jonny Retrofit]

please explain ?

Not being able to kill the ignition in a car is a serious issue. It is more worrying that the issue might be intermittent, lying in wait for that one time you really need to kill the engine.

I can't believe that the onus is on the customer to add a diode into the wiring harness to remedy the fault. This is clearly a design failure.

We would not sleep at night if our units had such a fault.