doug2060

I disconnected the purple wire as you said. It was the only purple one there but it did not directly go to the starter. It went to the starter realy above the fan. I disconnected it and the voltage only changed to 0.43.

doug2060

Could all this be caused by a bad pcm?

EinST

No, the poor PCM gets blamed for a lot of things but I don't see how in this case. The ignition switch is designed to supply enough power to the starter solenoid. There's a purple wire that show 0.43V with key on and presumably 0V with key off? It's connected to a coil terminal on a relay that powers the starter solenoid? This relay sounds like something jury-rigged to work around a short in the circuit from the ignition switch. As I posted before, the transaxle range switch on top of the transaxle sits between the yellow wire from the ignition switch and the purple wire from the starter solenoid. With the purple wire off the relay, take the electrical connector off the transaxle range switch and then measure the resistance to ground to figure out where the short is, i.e., which wire or the switch itself?

doug2060

I believe the relay may be factory but I could be wrong. Are you referring to the neutral safety switch? BTW, Thank you for your help. Will the wiring to the range switch keep the ignition from turning on? No dash lights etc?

EinST

Yes, it's also called the neutral safety switch. By "dash lights," if you mean the lamp test when the key is first turned on, that's something else. Except for the red wires (power source) the yellow wire (hot with key in start), the rest of the wires on the ignition switch should be hot with key on. You may want to measure voltages on both sides of various fuses instead of just eyeballing (if that's what you're doing to check them). Any fuse labeled I/P cluster or PCM should have battery voltage on both sides with key on.

doug2060

I've tested every fuse including the irrelevant ones. All check out. The reason I ask about the computer is because I get nothing. I can't even scan for codes. I have 2 good scanners (AutoXray Code Scout 2500 and an Equus 3160) and both will say connected once plugged in but cannot communicate with the computer at all. The say make sure ignition is turn to on etc. There is no lamp test when the ignition is turned on. Nothing happens. I nearly fully disassembled the dash to get a good look at the fuse block and wires and find no signs of damage. I opened the cluster too and found no signs of physical damage (burnt fuses, resistors, capacitors, etc). I even removed the computer (located in front of front passenger side wheel well below headlight) to test for power. It's definitely got power going to it. I just don't know if anythings coming out of it. With all this is mind I keep thinking it's the computer. But... I've thought that before on many cars and it never turns out to be the problem... Then again, I've never went through so much stuff to just find nothing else wrong.

EinST

I don't know what to say but to suggest going over the fuses labeled I/P cluster or PCM and verify the voltage in and voltage out across them with key on. From there, start tearing up the fuse blocks and check the connectors on the back sides.

doug2060

I edited my post above apparently while you posted to include that I had done all that and more. I've been doing it for 3 days now LOL. I've even redone some of it several times. I know the computer is usually the last possible thing when it comes to stuff like this. Is it even a possibility that it can cause this?

EinST

I had to sit down and go over what you've posted so far. The transaxle range switch is also connected to the PCM over multiple wires so that the PCM can tell the current range. Now, there's a possibility that the short is at the transaxle range switch or wiring, not to ground but to the PCM. A battery voltage to the PCM over a 5V circuit will fry various circuits inside. You may want to open up the PCM and look for signs of burnt components and traces. If that's the case, you'll need a new PCM and replace or repair the short in and around the ransaxle range switch.

doug2060

I opened the PCM but saw no physical signs of damage. There are other reasons why I am beginning to suspect the PCM though.

1. For the past year the oil light will come on at idle once the car is warm. I know there are many things that can cause this. The sending unit was replaced and it still did it. Using a pressure guage it tested in the normal. Sometimes it would never happen at all but in the past few months it always did it. Still shows normal under guage tool.

2. Over the past year the car will be at idle and start to shake and sputter and sometimes die for no reason and no check engine light or pending codes.

3. The theft system light came on about 3 weeks ago after the car seemed to lose power for a brief moment. After I turned the car off and restarted it was gone. Since that time the theft system light has came on during "lamp test" when the ignition is turned on but went off with the rest of the lights when the car was started. I do not recall the theft light ever illuminating during "lamp test" before this time. (I may be wrong and just never noticed).

4. Over the past 2 weeks. The car will lose power very briefly even when at 35 to 65mph. Like a missfire but the gages all drop slightly then shoot right back up. Still no codes. (In my experience this type of behavior will set a code in most OBDII cars). It has done this 4 or 5 different times over the past week.

5. I can confirm that the PCM for several weeks and possibly even months (dating back to cold weather) will not send a signal to start the fan. (mechanic shop confirmed this). I had to run the AC for the fan to come on. This was confirmed on a cool night a couple weeks ago when I turned the AC off and the car ran hot waiting on a train to pass.

6. The old fan motor which was replaced the night prior to this mess had a short in it. Once the car ran hot and the fan was identified as being weak I could push down on the connector and it would speed up but not to full power and if I let off it would die or reduce fan speed. If it didn't come on at all I could hit it on the back and it would start. This along with the fact that the fan has not been getting a signal from the PCM to turn on make me think that maybe a short in the fan somehow damaged the PCM. The new fan ran perfectly without issue but still would not be turned on by the PCM. (and yes all other related items were checked. I even replaced the temperature sending unit 2 times and all relays fuses etc are good).

7. My father in law next door likes to use my car to jump start his riding mower which doesn't even have a battery in it. I told him to stop last summer after he melted my jumper cables but I think he waits till I'm not home and does it anyways.

With all this in mind can anyone think of anything other than the PCM that would cause my symptoms? Some of the stuff above may have nothing to do with the PCM. Can the short in the fan motor even have any effect on the PCM?