EinST

No, the PCM is probably okay but is just not getting power through fuse 44. One side of the fuse 44 socket should be directly connected to the battery electrical buss and thus the fault is internal to the underhood fuse block. You can get around it by shunting power from the Accessory Power Outlets, Cigar Lighter fuse (fuse 34, underhood, which is also always hot) with an add-a-circuit and fuse tap. Hopefully the side toward the PCM is actually connected. See thread https://chevroletforum.com/forum/col...e2/#post215028.

As for fuse 47, what little resistance across the fuse, resistance at the probe contact point, and sensitivity of the meter, they all come into play at mV ranges. Anyway it should be close to the battery voltage. Since fuse 47 is downstream of the ignition switch, measure the voltage at its sibling, the Climate Control System fuse (fuse 46, underhood). Also, measure the voltage at the Ignition Switch maxifuses (fuse 1 and fuse 5, underhood), upstream of the ignition switch. Depending on the readings, you may be looking at a faulty ignition switch (what's behind the lock cylinder).

PC853

K. I will check it out. Thank you for walking me through this.
I'll post back tomorrow morning.

PC853

I have no voltage at Fuse 1 or 5, key in any position, either side of either fuse. ...same with fuse 34 & 46.

EinST

That's bizarre. Since you measured good voltage on most switched circuits downstream of the ignition switch with the exception of fuse 47 (did you measure fuse 46?), I don't see how there's no voltage at fuse 1 and fuse 5 that supply power to the ignition switch. They, in fact all 7 maxifuses in the underhood fuse block, are on the main electrical bus and thus should be always hot. Maybe the previous owner heavily modified the wiring in which case you need to tow it in for service.

PC853

I will double check everything and just go one by one through it again tonight. I appreciate you sharing your wisdom and giving guidance. Maybe I did something wrong.

The previous owner was my wife's grandmother who bought it new and rarely drove it. So there should not be anything non-manufacturer spec. If I can't reason through this by the end of the weekend I will be towing it in on Monday.

Perhaps I have a corrosion issue with my positive cables between the battery and the fuse box. The positive battery terminal does show corrosion, I have seen much worse however.

PC853

After scrubbing off the terminal a little more I got a clean, steading reading of roughly battery voltage at fuses 1 & 5

EinST

I take it there's no change with the other fuses that were showing no or lousy voltage? In a way that's actually good since hard failures are easier to find than the intermittent.

PC853

Yep. Ignition switch was it. got a ~$40 Dorman unit shipped - the local dealer wanted $200 for just the switch?! swapped in the Dorman switch and turning the key, I now get all the check lights to come up like they should. Crank it and it fired right up!

I cannot thank you enough, EinST!!

EinST

Congrats and thanks for the update. The ignition switch had a lot of current going through it and thus tends to wear out. It's not like that in the current generation Malibu.

chazwel

Awesome Job....