Ballist Resistor location 2000TC

#61
Haven't been able to get over the garage with all this wet stuff coming down, but had a word with Mark Grey again and told him I'd run another wire in place of the ballast wire, as he suggested before, and that things were the same. The Ignition switch may be at fault keeps popping into my head because the engine starts when I turn the key but stops when I release the key after starting. I also mentioned the brown wire to him that's hanging by the starter and alternator, mentioned in this thread Loose wire and he's of the opinion that it should be connected to the alternator, which is what I thought when I found it in March, but while there are two holes in the alternator casing I can't see any connecting male spade for the wire to connect to. My thoughts on this is, this brown wire may be the one that runs from the alternator to the starter and then supplies a live feed to the +side of the coil. Any thoughts. Back over the garage tomorrow and car will be up on the ramps so I can have a good look at this.
 

roverp480

Active Member
#62
Live side of coil is ignition controlled . From what you are saying the ballast bypass is working from the starter as the vehicle starts but the feed from the ignition to the coil is not. If all your gauges etc are working when you switch on the ignition it must be a break or poor connection in the feed from the ignition switch to the coil. As the starter works, controlled from the ignition switch, there must be power to the switch itself.
 
Last edited:
#63
I haven't bypassed the ballast wire, I replaced it with another wire to see if the ballast was the fault, but it wasn't at fault. I will reinstate the original ballast resistor wire, as there is no difference in what happens. Engine starts at the turn of the key but on releasing the key the engine stops, as it's been since this fault began. I thought the ignition switch was at fault when this began. My opinion is the same, will have to get a switch and see if the engine runs.
 
#64
I haven't bypassed the ballast wire, I replaced it with another wire to see if the ballast was the fault, but it wasn't at fault. I will reinstate the original ballast resistor wire, as there is no difference in what happens. Engine starts at the turn of the key but on releasing the key the engine stops, as it's been since this fault began. I thought the ignition switch was at fault when this began. My opinion is the same, will have to get a switch and see if the engine runs.
If the switch is faulty then the ignition light will not be lit when the engine stops and the gauges will not register. With the switch in the "on" position you should see about 7 volts at the coil + terminal with the ballast resistor in place. It sounds as if the coil is not receiving power when you release the key so you need to trace back from there.
 
#65
"It sounds as if the coil is not receiving power when you release the key so you need to trace back from there."

Yes, that I can agree with, no power at coil when key is released. As mentioned earlier, with live direct from battery to the coil+ the engine runs fine. But that bypasses the ignition switch as I can turn ignition off and take key out and engine is still running until I pull the live feed off the coil+ .
 
#67
Haven't tried anything when the engine is NOT running after trying to start. Though when I put a live feed from the battery to the coil+ and run the engine have tried lights, wipers, hazards and indicators and all work while key is in the ignition. When I take the key out and engine is still running nothing works except lights.
 

roverp480

Active Member
#68
That means the wire to the coil from the ignition switch is not connected, either a bad connection or a break in the wire . According to my P6 Manual on 1973 vehicles there is one white wire from the ignition switch to the fuse and then it splits to ignition and the other items such as wipers indicators etc.. I wonder if there is a bad connection in the fuse box.
 
#69
What manual are you looking at. I only see two wires going to the +coil, one from the fuse 19 on diagram through the Ballast wire to the coil and the other from +coil to the starter motor. Will be checking the fuses this morning weather permitting.
 
#70
Just back from garage. Checked all fuses and they look good, though I didn't test them. Ran a wire direct from battery through the original ballast wire and checked voltage, had 11.75. So I assume this wire is good to go but didn't connect it up, ran next test with the ballast wire I fitted earlier. put key in ignition turned to on position and checked voltage at +coil, was 11.75volts. Again turned key to on position with radio on and radio works, ignition light on oil light on. Turned key to start the engine, engine starts and stops when key is released to on position. NO radio or ignition light or oil light. So I assume on position is live when key is first turned the after starting the engine and key returns to on position, on position is now not live. I think I need to get another ignition switch to test.
 
#71
Oh and I checked the voltage at the +coil side before starting, which was 11.75volts and then when engine had started and stopped when the key was released to ON position I checked voltage at +coil again and it was 0 volts.
 

cobraboy

Well-Known Member
#72
I realise that you have cut / changed / replaced wires at the fusebox, and also run a separate new wire to the coil and have run the engine this way. Have you actually looked at the rear of the ignition switch to see if a wire there has become disconnected ?
 
#73
"replaced wires at the fusebox"

No I haven't replaced wires at the fusebox, where have I said that. I replaced one wire, the Pink/white ballast wire behind the dash that runs to the +coil, that's all. No I haven't looked at the rear of the ignition switch, I have tried to look at it but it's not possible to see the switch as there is a metal plate and a rubber boot over the rear of the switch and in the way. The only way to see that is to take the switch out, which is probably going to be my next job.
 
#74
Went to see Paul Stabbins of Get Smart Classic Car Restorations and bought a used ignition switch from him to run a test. I took the upper panel out in the cubby hole above the radio and located the ignition switch cable connector, unplugged it and plugged the used switch in and turned it with a screwdriver to the start position and no start, same as before. unplugged it again and checked both switch plugs side by side and they were slightly different. Plugged the original back in and turned the key to see if I had auxiliary items on and all looked good so tried to start the engine again and it started and continued to run as normal. I turned it off and then started again and it ran, so it looks as if the problem has solved itself. Bad connection is the only thing I can come up with. Thanks to all for your input, it's been interesting, frustrating and sleep depriving but it looks like a good end to this mystery. Just have to put the dashboard back together now.
 
#75
OOPS Spoke to soon. pushing the switch connecting block back up under the dash while the engine was running the engine cut out, so I pulled it back down and started the engine again and it started and ran. Pushed the block back up and engine stopped again so looks like the problem is the connecting block or there may be a break in the wire at the block. Contact cleaner on the block contacts tomorrow.
 
Top