No Start - No guages - Cranks Strong

[jerry598]

Just returned from a long trip during which I noticed the idiot lights and tach flickered occasionally. Now truck won't start and guages and idiot lights are not working, but engine cranks over strongly. Idiot lights show faintly and guages move slightly when key is turned on after dark. Tested batteries and cleaned cables. LH battery with a bad cell was replaced. Battery cables show continutity and appear OK. All fused checked out OK under hood and at instrument panel and power is present at these locations. I now suspect a faulty ground connection or maybe a faulty ignition switch because the lights and guages have come on 3-4 different times during all the many attempts I've made to fix the problem. When they do come on, the engine starts without any trouble and does not stall out. I also cleaned the ground connection on the RH rear manifold, but did not trace those wires to their source. Can anyone tell me if that connection or what other ground connections could be causing this and where they are located? What else might cause this problem?

[tom.mcinerney]

Jerry-
This sounds like a fuse.... 'ECM1' , 'ECMB' or similar. Consider wiggling or renewing. Ig switch may be culprit.

What year , model, mileage, etc... ??

[jerry598]

Thanks for the reply, Tom! This is a 1995 K3500 w/120,000 miles on it. I tryed your suggestion on the fuses, but wiggling and replacing did'nt work. Also tested battery voltage at the terminals on the underhood fuse/relay center, the glow plug circuit fuse, and the glow plug relay. All show 12.5 v. But, with the key turned on, I only get 2.5v at the ECM-1, ENG-1 and fuel sol. fuses. I get the same 2.5v when I ground the "L" terminal on the alternator harness (disconnected). My book says I should get "battery voltage" at the "L" terminal, but says nothing about the fuses. Are those low voltages an indication of a problem with the ignition switch? Should they be 12.5v? I also tested resistance at the fuses with the positive battery cables disconnected and key turned on. There was some resistance at the fuses (.5 ohms). Thanks very much for your help, Tom. Any other ideas?

[jerry598]

Forgot to mention that the glow plug relay also does not cycle on like it should when key is turned on and I can hear no sound from the lift pump (if that is supposed to cycle on). On those few trys when the guage lights and instruments did mysteriously come on like they should, the glow plug relay also clicked on and the truck started easily. But, that happened only 2-3 times out of a hundred or so attempts to start.

[jerry598]

After more research on the diesel page, I'm going to focus on the ignition switch. Seems that ED2000 had identical symptoms to mine, and it turned out to be the wires to the switch. I will get back with the results.

[tom.mcinerney]

Jerry
For whatever reason the '95s seem to really profit more than most from new ig switches.

It isn't hard to replace, but take your time removing i think 4 screws from underside of the steering column cover. 'Billman' offerred good advice concerning removal in posts about a year back.

I think there's a ground to the instrument panel behind (aft of) the relay block beneath the steering wheel...mine to a tubular support.

You seem to have lost multiple circuits , so switch/ground(s) may cure.

>>My book says I should get "battery voltage" ....
Is this an OEM Helm manual??

**
If the switch contacts or ground are really bad connection, they'll show good voltage with no load, but as soon as the circuit is 'ON' , the voltage will plunge.

[jerry598]

The problem for sure is in the ignition switch. I removed the shrouds, turned the key to on and wiggled switch. All guages powered on when I put upward pressure on the bottom (the contact area) of the switch, so it must be just a bad contact in the switch harness. Would I be wrong to replace it with a salvage yard switch? Or should I spend the extra money for a new switch? Any suggestions on how to deal with those torx head screws? And thanks again for all the help!

[tom.mcinerney]

>>how to deal with those torx head screws?
Lost me. "Torx head driver?" {missing~!}

I did drive around to a couple stores before getting 'right' drive, but noted that a slightly undersized one worked .

I would definitely not go 'used'...the electric system is comprised of under gauge wire, in lengths too short. Many of us have improved performance/reliability by installing relays with bulky wire in several circuits , to relieve load on mechanical contact points, while delivering more voltage/power to components . Not that a used item wouldn't work , just nice to increase reliability when maintaining a troublesome system. Keep in mind that low voltage and arcing will deteriorate downstream components.

Kennedy now offers a nice rig for the OPS/LP circuit; he's sold a headlamp upgrade for some years.

[jerry598]

Thanks for the advice, Tom! We have a hard time finding the right tools in this little town, hence the problem with the torx head screws, but I got around it and have a new switch on order. I'll definitely study the rest of the diesel page for other improvements.