[rolling money pits]

Posted on a vehicle specific forum but figured I would poll the group here…

95 C1500 4.3

Yesterday all was fine, this morning not so much.

Went to start and before I even hit start I noticed fuel and oil pressure gauges acting weird, fluttering. Hit start and a barely audible click, then nothing. Prior gauges are pegged past full/80 psi. Blower motor not working, turning speed control knob makes the OP gauge needle flutter with each notch/click. Radio works, wipers and interior light do not.

Headlights on fully as are signals and flasher functions. Keying start with headlights on shows NO change in brightness. Additionally, keying start does absolutely nothing, no click at solenoid, it’s as quiet as can be.

I monkeyed around with wiggling lock cylinder and moving shift lever into neutral while keying start. Multimeter has gone AWOL…so I’m flying blind.

Side post battery, maybe 4 months old, and I’ve removed cables and retightened in slightly different position. Starter was new NAPA unit, maybe two years old now. Again, truck was running perfectly fine until this AM….. was given no prior warning of a battery or starter/solenoid going south.

A cursory search across the web indicates a bad ignition switch could be the problem, do the above symptoms point in that direction? 99K miles, and I’m going to assume original switch.

Thx

["QUICK-SILVER"]

That 95 have fusible link wire or maxi fuses?

Blown fusible link would be my first guess.

FWIW Switch life is more about cycles than miles.

Clay

[rolling money pits]

I haven’t delved into links/fuses yet, that’ll be next.

I imagine this bad boy had a bazillion cycles on the switch. It was a former HVAC company work truck, and as such probably got a week’s worth of “normal” usage in one day.

[Lemans64]

When ignition switches go bad on those usually they loose the PRND321 indictor on the dash. also the trans shifts weird. looses power to shift solenoid.
But check the PRND321 indicator with ignition on.

[rolling money pits]

PRND321 only lights up in the on position, I guess. Nothing in acc, which I assume is still when keyed backwards.

In the run position it goes out.

Funny you mention trans shifting…I did notice it being not quite normal recently, nothing egregious, just slightly off. I don’t drive the truck that often, mostly my 3 pedal vehicle.

[mgarblik]

I can make a few suggestions to hopefully head you in the right direction. Step #1 in any electrical diagnosis is to have a verified fully charged, known good battery installed with good connections. A four month old battery means absolutely nothing!. I have replaced plenty of them. Either install a known good battery from another vehicle or have this one checked for voltage, load and capacity. All three are important. Once that is accomplished go to step 2. That would be to verify voltage to the "S" terminal at the starter with a test light or voltmeter. That's the small lead. Have a helper hold the key in the "crank position" while you test. If your good there, the ignition switch, all the wiring from the battery to the starter is probably good. Step 3 is to remove and have the fairly new starter tested. A two year old parts store starter can easily be dead. See this every day. Replacement auto parts are complete crap the last 10 years. Makes diagnosis and repair quite difficult. However, the OE ignition switch, especially GM is quite robust. All of the weird symptoms, including the transmission issues can be attributed to a battery or connection issue. Good luck.

[rolling money pits]

Thanks.

Multimeter was located, battery 12.5 - 12.6

I’ll monkey around with your suggestions. From what I’ve read thus far, while not “common”, ign switches going bad on these vehicles isn’t out of the ordinary.

Another related question: further research shows me folks with these trucks, when it comes time for a new battery, ditch the side post in favor of a top. Are those screw in top post conversion lugs an effective solution until it’s time for a new battery? I plan to upgrade cables to bigger gauge, and they would be top if I can get away with those lugs.

Thanks again.

[mgarblik]

Although 12-5-12.6 V sitting voltage is good, it is still possible the battery doesn't have any capacity. It's a rare failure, but I have seen it. If you don't have a way to test that, put your volt meter on the battery and turn everything on you can think of. Lights, blower motor on high, rear window defogger if it has one. Battery voltage should stay above 11.5 volts for 15 minutes. If it does, the battery is likely Good. Post conversions are fine IMO. Make sure the top posts won't touch the hood or any metal when you close it.

[Joe's Garage]

We had a 2000 Suburban a few years ago that had various electrical gremlins that came and went. Weird shifts, dashboard glitches, turn signal issues. It even threw some codes for knock sensors and others.

We discovered that the positive battery cable was heavily corroded between the two mounting 'terminals', inside the plastic protective cover. It split there and one cable went to the starter and the other went to the power junction for the body.

When we removed the plastic cover and disassembled the two portions of the cable - actually the two cables - and cleaned off all the corrosion and junk growing in there (including a soak in baking soda and water until it was ALL neutralized) and then wire brushed it really well and reassembled it was fine.

Just a thought.