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Discussion Starter #1 (Edited)
Hi guys Ive got what I am hoping to be minor electrical gremlin to track down. Just as background info, Ive got a 95 g3500 with a naturally aspirated 6.5l db2 injection pump (no pmd). Anyways, In the past few weeks Ive noticed that when i turn the ignition, the "sensitivity" of the ignition switch has been decreasing a bit. Meaning that I am getting no response from the key turn except in one "sweet spot" where the vehicle will start. The vehicle would start fine once I hit the right spot and I got power to the starter.
Recently it has become extremely more finicky, and now the situation has deteriorated and my ignition cylinder seems to give me no response.

So heres what I know:

Key turned, I get power to my glow plug light, interior lights, radio. maybe to my gages. I can actually see the mph gage needle slightly twitch during the key turn, and the battery needle works, so i guess they work. But of course no power to starter.

Im not the best with electrical, but my initial guess was that my ignition switch was starting to go. Any thoughts? Loose ground somewhere? anything I can test to narrow this down further? Thanks in advance for any help fellas.
 

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Could be. I have a little round ammeter I bought 40 yrs ago which lays on a battery cable and gives the amperage going thru the cable. It will tell you if the starter is drawing current with the key in the start position. If you have one and it is drawing enough current, it tells you the problem is in the starter and not the switch.
 

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Probe the CRANK fuse in the fuse block in the drivers side of the dash with a 12v. test
light while you try to crank it. If the light glows then power is headed to the starter, if not then you probably need an ignition switch. 1995 does not have a starter relay like the 96 and up do. The crank fuse does not feed the starter, it send power to the lift pump relay while cranking.
 

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Probe the CRANK fuse in the fuse block in the drivers side of the dash with a 12v. test
light while you try to crank it. If the light glows then power is headed to the starter, if not then you probably need an ignition switch. 1995 does not have a starter relay like the 96 and up do. The crank fuse does not feed the starter, it send power to the lift pump relay while cranking.
Added to the FAQs :thumb:
 

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Discussion Starter #7
thanks alot for the help fellas, im gonna jump into this today and see what i come up with. not sure if my 95 has a crank fuse because i have a mechanical lift pump, gonna see what i find..
 

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Just realized you have a van but should still have a crank fuse. Might be marked CRK.
 

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Discussion Starter #9 (Edited)
ok so thanks again for all the insights my friends. I finally got some time to poke around and I'm finding that:

I cleaned up and inspected all the grounds that I could find, especially the rear passenger manifold ground.
I cleaned up and tested the batteries, they are reading and looking good.
Ive tested the lead to the starter solenoid from the battery, and I'm getting 12v there.

Any thoughts on where to locate/test the ignition switch (switch end of my solenoid).

I know I can jump the switch on the solenoid and see if the starter kicks, but I'm working by myself with no jack stands, blocks, etc, and the starter is so hard to get at on these vans, it would be somewhat epic.

It would be great if I could move to ruling out/testing the ignition switch, plus i actually suspect this is where my issue is anyway, but of course I don't really know much about electric. I read the above link on testing the ignition switch but I'm not quite understanding it. Wondering exactly how to check for power at my ecm fuses?

I don't know if I made it clear before but my starter won't crank at all, and I have not been experiencing any stalling or things of the sort while the car was actually running.

thanks again all.
 

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Discussion Starter #10 (Edited)
a quick update, i also checked my voltage on the switch stud (the small one) on my starter solenoid, with the key in start position. didn't get much on it. i put one lead on the stud and one grounded to the body (guessing thats right).. but anyway I'm assuming its supposed to have decent voltage when the key is in start position, don't know how much, but is this correct? and can i assume that if there is no voltage to this stud that my problem is probably in the ignition switch?
 

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You should have 12 volts in the start position there. It doesn't prove it's a bad switch since there could be a bad connection somewhere between the ignition switch and the solenoid. You need to measure the voltage coming out of the ignition switch heading towards the solenoid switch to see if the ignition switch is providing 12 volts. A simple solution (temporary or permanent) would be a push button switch directly from a 12 volt source to the solenoid, bypassing the ignition switch.
 

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There will be an elect. connector on or near the steering column that goes to the ign sw.
there should be a heavy gauge purple or maybe yellow wire on that conn. That would be the starter sol. wire that runs to the starter via a neutral safety switch and I think you have a starter relay somewhere but not sure about that. Check that purple or yellow wire for 12v. in start.
 

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Discussion Starter #13 (Edited)
Thnks for the help gentlemen. I am at the point of trying to find information on how to remove the steering wheel etc to access the ignition switch and everything. You are correct on the large purple wire feeding the solenoid switch, but i can't see it under around the steering column where it might connect to the ignition switch or something. Im also trying to search around to find what codes my dash lights are throwing. my abs light is blinking in the start position.. Also I was reading around and wondering, do I have a neutral safety switch on this vehicle if its an auto transmission, if so where is it? anyway I'm back at it.. thanks again
 

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Neutral safety switch should be on the steering col. near where it bolts to the firewall under the dash. It is a half moon looking switch and is mounted on the top side of the col.
Two of the wires going to it will be heavy gauge purple. One to the bulkhead conn. bottom row, one to the ign. sw. That is the starter sol. circuit. A photo of your gauge cluster and your RPO codes in the glove box would help me identify what you have.
Is the 8th digit of your vin "Y" ?
 

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Discussion Starter #16
So I couldn't find that purple wire, which eventually led me to dropping the steering column and digging in to find the ignition switch.. i could barely get at it, but i pulled the ignition switch (cause i couldn't even get the harness off it) and i figured I would at least test the wire for continuity to the solenoid (going out to do that now, Ill also get the VIN).. I definitely don't see any half moon type switch but i will look again. Ive attached some photos of my wiring situation. The van used to be owned by the fire department so they kind of had their way with things.. thank you for your help with this.
 

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Discussion Starter #17 (Edited)
You are correct the eight digit of the VIN is a "Y". I just did a continuity test on the big purple wire from the wiring harness to the solenoid and it tested fine. Although there is a smaller green wire that comes off the solenoid at the same stud with the purple wire. I can't find where this one leads...
 

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The smaller Lt. green/black wire on the starter sol. goes to the glow plug controller.
The purple start wire should go straight to the neutral switch from the ign. sw.
Apply 12v. to the purple wire, if the engine cranks you have your answer.
 

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Discussion Starter #20 (Edited)
thanks glagulator you the man. so i guess ill just jam some decent gauge wire in the purple connector on the harness and touch it to the positive battery terminal?..
 
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