Hello everyone, long time no post...

I have a problem with my '87 Buick LeSabre 3.8 that has me completely flummoxed.

My mother had been driving the car (204k on the Intrigue, intake manifold gaskets finally let go) and she got stuck at a friend'* house, was just about ready to call a wrecker, and one final attempt she got the car started and she drove it home. As is typical for her, she could not tell me anything that happened leading up do/during the time time it would not start.

First thing I did was check the obvious - battery voltage acceptable. I turn the key, and there is literally NO sound from the starter, nor from the solenoid.

Talked with the previous owner (next-door neighbor whose elderly mother owned the car before him), and to our knowledge, the starter was original. I figured to just go the obvious route and swap out the starter/solenoid - it'* 28 years old and has 143k on it.

Much to my dismay, spring thaw happened, and the old girl sunk down somewhat in the muddy driveway (the Buick, not my mom ) and it took some finagling with a jack and some blocks of wood to get underneath enough to swap it. (GM engineers thought it would be great to bury the starter underneath the front exhaust manifold...)

New starter, and what the heck, threw in a new battery too. Turn the key... NOTHING. No click, no noise, nada. Still no crank from the starter.

So I go through the "fun" of replacing the starter switch. Just pieced the car back together today, and still no crank. The replacement switch is Carquest brand, made by BWD (Borg Warner), which I know is typically crap, so I can't be positive that the new switch isn't bad. However...

I also thought, maybe the PNP switch (Park-Neutral Position, but I've also seen it called Neutral Safety Switch and other names). My Haynes manual, as usual, has information on everything except what I need to know. In this manual, the wiring harness diagrams are a JOKE.

They only include diagrams of front and rear lighting across multiple Buicks and Oldsmobiles, one diagram of the IC3 ignition system, and one diagram of the ESC system. Not exactly helpful in any way for diagnosing anything, unless somehow I take leave of my senses and don't know how the tail lights work. LOL

The only info I've been able to find on the PNP switch is that connecting the yellow and purple wires together will bypass it "temporarily" for testing if the switch is bad. I have tried this and still cannot get the starter to crank, but being the internets and such, I have no idea if these are the right wires to check, or even if the bypass has to be tried while the switch is plugged into the harness. (No "brain" in the transmission, so I assume it only does the Park-Neutral safety thing and the reverse lights.)

Before anyone offers suggestions, please allow me to eliminate some of the possibilities:

Yes, I have tried starting the car in Neutral, and even held the key in the "Start" position and moved the shifter through its entire range (my inept way of testing the PNP switch originally), with no attempt from the starter.

There is *NO* antitheft device on this car, factory or aftermarket, and there never has been. No remote starters, no pellet-in-the-key or recalibrating keys to the ignition lock needed. The car is pretty much a barebones 80'* car.

I'm not sure if there is a starter disable relay, because the pages of my happy Haynes manual is basically only good for wiping my greasy fingers on. Obviously, it is quite literally a pain to rip the exhaust manifold off again to access the starter & solenoid to test for voltage at the solenoid, so is there anything else I can check before I get into that?

Thanks in advance for your suggestions!

You could turn the the key to power on, and jump a screwdriver across the terminals of the starter and kick it that way. If nothing happens, swap the starter.

Yeah... Whether I'm jumping the posts, or pulling the new starter to reinstall the original starter (glad I kept the shim!), I have to pull the front exhaust manifold. There'* no way my clumsy fingers would attempt to do it without, I know I'd end up arc-welding something accidentally.

I was just hoping there was something else related, or some weird design they tried, that I had missed. I've seen GM have some strange ideas in the past...

First, see if you have bat power on the purple wire to the starter solenoid "*" terminal, with the key in the crank position....if yes, replace starter...

If no power, then try starting in neutral.....if it doesn't start, go to the P/N switch on top of the tranny, driver'* side, rear......probe the purple wire out of the switch for power with key in crank position....if you have power, you have an open in the purple wire to the solenoid...

If no power, check for power on the yellow wire into the P/N switch with key in crank position....if you have power, bad P/N switch.....if no power, check for power on the yellow wire coming out of the ignition switch, that goes to the P/N switch....

I assume the starter is correctly connected....

I am not sure, but there may be a starter interrupt relay between the ignition switch and the P/N switch....but I don't think this year vehicle uses a theft deterrent circuit...

Thanks. You assume correctly. Done quite a few starters in the past 20 years. I'm also OCD so I check my work three times over... And, it'* connected the same way the original starter was hooked up.

I had considered the thought that there is a wiring issue between ignition switch and PNP, or between PNP and solenoid. When I pulled the plug on the PNP to jump purple to yellow, there was a significant amount of corrosion, which I cleaned out the best I could.

Thanks for confirming the yellow and purple wire tests. I was a little uneasy about a Google search result on one of those "Pay-to-ask-an-expert-and-click-here-if-my-answer-helped-you" sites!

I think you're right. About the only theft-deterrent feature of my car is the fact nobody under 50 wants to drive it. There was an OPTIONAL anti-theft package that, according to the options sticker, it doesn't have...

Knowing GM, probably about 80% of the option is already installed. I would assume the option was VATS-I (pellet-key) since I think Cadillac was offering that system at the time, so there could be a starter disable relay somewhere. I'll see if I can find any further data.