Key Doesn't Turn Engine Off

[stev]

Yup so remember when I said I had a exciter wire connected to a different part on the fuse panel, that black wire on fuse 11 was the exciter wire. I guess I completely forgot about it and it was powering the other two fuses keeping the main relay for ms on. So I removed it and started the car then pulled the key out and it turned the engine off. Thanks for the help.

 

[apachechef]

Yup so remember when I said I had a exciter wire connected to a different part on the fuse panel, that black wire on fuse 11 was the exciter wire. I guess I completely forgot about it and it was powering the other two fuses keeping the main relay for ms on. So I removed it and started the car then pulled the key out and it turned the engine off. Thanks for the help.

start looking at a bypassed exciter circuit at alternator, and also the brown wire at the starter, used to energize the ignition at full 12v during cranking, check where it goes.

glad you got it working!

 

[bobxyz]

Glad you figured it out. You'll need to install the cluster, or add a blocking diode in the exciter wire, to fix the issue. If you just disconnect the wire, the battery may not charge.

I have a benchtop power supply and boxes of spares parts readily available so, being curious, I measured a few relays and instrument cluster bulbs.

The alternator failure bulb can definitely backpower switched +12v and keep one relay energized. It might be able to keep two low-current relays energized, but it definitely can't keep three relays energized.

[I measured a handful of relays and they draw 120mA to 150mA at 13.3V. Most of them dropped out/opened at 35 to 40mA, but one Bosch relay stayed energized down to only ~25mA. The cluster bulbs draw 65mA to 85mA @13.3V. When wired in series, the available current from the bulb is less than the 65-85mA.]

 

[VB242]

I've been running my 100 amp Denso off of a relay without going through the charge indicator light for a couple years now, I haven't had any problems. I do have a digital volt meter in one of the switch spots to keep an eye on things. Never seen it over 14.2 volts.