My 'Burb, she no crank!

[Lightyear]

My 'Burb has developed an attitude. It will cycle the plugs (modified controller), but does not crank. Starter tests out okay. Turn the key, controller cycles, voltmeter on dash drops with the plug cycle, then only comes back up a little bit. Turn to start, no crank, no click, only voltmeter still showing lower than normal. Batteries are brand new as of Saturday (AC-Delco replacemetns from my local GMC boys). I'm thinking bad hot lead from starter to ignition switch, or maybe bad lead from ignition switch to small terminal on starter. Any ideas, anyone? Thanks!

[john8662]

When does it occur, hot or cold?

Test for voltage at the S terminal on the starter when cranking, this will reveal ignition switch problems (use a test light).

[Warren96]

You no check grounds.Clean and coat the grounds with a dielectric grease,she get very cranky!

[JCalvin]

You might want to also check the transmission wire it has one to ensure the engine is either in neutral or park

[Lightyear]

Thanks for the tips...if the rain holds off, I'll crawl around and see what I find. This problem happened the first time hot. Shut down hot in the driveway, jumped back in 5 minutes later, no crank. Fooled with it for a couple of days. Charged batteries and ultimately replaced both, had the starter tested. At one point, it would crank and start right up. I tried that 3 or 4 times, then back to no crank.
I know of the ground strap from block to firewall and battery to chassis; which others are in there? For the neutral tranny switch, how many leads should be there? Mine has a 2-wire connector that only seems to run the backup lights. I'll check the S-terminal too, and report back later. Thanks, all!

[ZZ]

A dollar to a doughnut says either the starter solenoid or the neutral safety switch is bad.

[Lightyear]

Here's the latest: There is power to the starter, and power from the starter to the junction block on the firewall. There is NO power to the purple wire at the solenoid, and no power in the purple wire in the harness along the firewall. I removed the engine control/ignition switch before I ran out of light, and tested it with a VOM. There is only intermittent continuity between the terminals from battery to the solenoid (purple) terminal when I move the switch slider to 'Start'. So I think I've narrowed it down to the ignition switch or the entire purple solenoid wire. Does this make sense, or am I missing something else? Thanks again to all.

[john8662]

So..

It's either the ignition switch (electrical part, not tumbler key assembly), or the neutral/park safety switch for the transmission.

They are both on the column underneath the dash.

[ZZ]

Here's the latest: There is power to the starter, and power from the starter to the junction block on the firewall. There is NO power to the purple wire at the solenoid, and no power in the purple wire in the harness along the firewall. I removed the engine control/ignition switch before I ran out of light, and tested it with a VOM. There is only intermittent continuity between the terminals from battery to the solenoid (purple) terminal when I move the switch slider to 'Start'. So I think I've narrowed it down to the ignition switch or the entire purple solenoid wire. Does this make sense, or am I missing something else? Thanks again to all.

The purple wire will only have power when the ignition switch is in the start position and the tranny shift is in neutral or park.

[Lightyear]

You all have certainly confirmed my suspicions. My next steps are to basically 'hot-wire' it to see if it cranks. I do have new ignition and neutral safety switches standing by.
As far as the neutral switch, there was only a single connector on it, with 2 wires. Is that correct? I replaced it about 18 months ago, and it's been working until now, so I don't think I mis-connected anything, but...More later after I fool around under the dash tonight. Thanks again...y'all are a great resource.

[ZZ]

You can temporarily connect the two wires on the safety switch long enough to verify it's operation.

[Lightyear]

If my backup lights work, so does that mean the switch is good? I did jumper the two leads off the NSS together; no crank, but good backup lights.

[ZZ]

The backup lights & starter are on different parts of the safety switch. One can work and the other not.

[Lightyear]

Interesting...I only found 1 connector on my NSS, but yet there are 2 sets of paired spade terminals. And the wired connector only fits 1 pair. Maybe I need to crawl really deep under the dash to see what's going on...or coming off.

[ZZ]

What color are the wires that you're finding?

[Lightyear]

I'll tell you once I get home and crawl under the dash again.

[X1TX]

Even if the switch works that's only half the problem. It could have 'moved' or clocked over a bit. If it's mislocated it won't let you start. I had an old column shift car that I had to relocate the switch on once in a while because it would drift. Just because the switch works don't think that's the entire issue with the switch.

[ZZ]

I didn't think of that. I never had the drift to affect starting; only the backup lights. I have to set mine on my '90 at times now to have backup lights in reverse, but it always starts.

[Lightyear]

WOOHOO! She cranks!! It turns out that the ignition switch was faulty. Hot-wiring the ignition hot input to the solenoid wire made the starter kick, so I figured all the wiring was good. Put a new ignition switch in and bang - crank. Thanks to all for your suggestions. Next is figuring why my plugs cycle randomly and intermittently, a problem in an old post I have yet to solve.