Struck by lightning?

[JohnW]

Hey I need some help. I was driving in a heavy thunderstorm when alot of things stopped working. I don't really think I was stuck by lightning, but the list of things that stopped working is strange. Before I took this trip, I was having issues with the liftgate latch staying locked, no rear wiper and not license plate lights. My remote locks worked, but not as good as they did before. I think it is in the wires that flex in the hinge, but I have not found one broken so far and I have not had time to work on it. I did not want the hatch to stay locked on me so I unplugged the hatch lock actuator, which meant the rear hatch would always be unlocked. I taped the plug so I am pretty sure it did not short out.
Now back to the big problem. Below is the list of things that went out all at once while driving at highway speed.
All gauges except tach and speedo went to full left.
6 warning lights came on the dash. Airbag, ABS, low fuel, some weird picture of the wheels and driveshaft with a wrench and I forget the other two. (not the check engine light)
Radio went dead, no lights no sound.
All windows, locks, etc that are controlled on the drivers door and passenger door went dead.
Oddly the rear windows work from the rear door controls (power mirrors still work)
The heating/ac display looks normal, but the a/c no longer works. Blower still works
The display no longer shows the transmission gear selector. It shows the letters PRND... but the gizmo that shows you what gear you are in is gone.
The digital display for things like gas mileage, oil change and such now are blank. Like for the oil life it shows __%
The cruise control is dead.
Their is probably more not working, but that is all that I noticed.

What I know that still works.
I was 100 miles from home when this happened. I was concerned the charging system might be dead too, but everything seemed ok from a voltage standpoint for the whole trip home, so I think the charging circuit still functions. (no voltmeter to tell with)
I was afraid to shut the envoy off till I got home, but the starter works and it starts right up.
wipers and headlights work. (good thing, I needed both to get home)

I have checked both fuseboxes and don't see any blown fuses. This problem seems to be involved with so many functions that I figured somebody would know what could go out or what fuse/relay that could blow to cause this many malfunctions at once.
This is on a 2005 Envoy xlt awd 4.2 with 100k. I have owned it 9 years and it has not had any previous electrical problems. (no hacks in the wiring and everything did work on it)
Thanks in advance for any help.
John

 

[mrrsm]

Get a can of some CRC Electrical Contact Cleaning Spray and remove all three of the PCM Connectors and thoroughly spray out the innards of the cables and the inserts on the PCM. Don't go crazy with the stuff in the PCM side... just enough to displace any water and dirt that might have been splashing up and inside of the unit while driving through and around so much water. Give them a few minutes to dry and if they are still damp... run some warm air from the Wife's-GF's Blow Drier at a distance far enough away not to ignite the fumes from the CRC cleaner or damage the PCM or the interior of the three terminal cables and plugs.

These connectors have an in-dwelling elevated plastic gasket that can be improperly installed and become easily dislodged and canted and allow damp air or water splashing about inside of the PCM. You will be able to recognize the problem by inspecting each seals for any strange flat spots that look like the plastic grommet slipped to one side and got squashed. Replace all three when time permits. After everything is reattached and tightened down snugly with no added sealant or lubricant... start the vehicle and assess all of the electrical things that misbehaved prior to this clean up. From a "loss of control" circumstance that presented itself when the storm hit your vehicle... checking at 'The Source of the Nile" electrically speaking makes sense as a good place to start when searching out the problem.

 

[JohnW]

Well it figures 2 minutes after I post my thread, I read that Bmonkey has a similar problem in a similar envoy. His thread mentioned a battery draw after the envoy was shut off. I had not touched mine since I got home 5 days ago and was expecting a dead battery. But to my surprise, when I turned the key on, the radio came on. I started the engine and everything works. There has been one small change since we got back. The kids with me had 2 of those usb power adapters plugged in the cigarette lighters during the trip. They were not removed till after I got home. I don't know if they worked after the problem hit or not. I have never had those plugged in my envoy before. I think they are just a simple power adapter, but maybe they made the computer mad. Any thoughts/experience with those gizmos?

 

[JohnW]

Get a can of some CRC Electrical Contact Cleaning Spray and remove all three of the PCM Connectors and thoroughly spray out the innards of the cables and the inserts on the PCM. Don't go crazy with the stuff in the PCM side... just enough to displace any water and dirt that might have been splashing up and inside of the unit while driving through and around so much water. Give them a few minutes to dry and if they are still damp... run some warm air from the Wife's-GF's Blow Drier at a distance far enough away not to ignite the fumes from the CRC cleaner or damage the PCM or the interior of the three terminal cables and plugs.

These connectors have an in-dwelling elevated plastic gasket that can be improperly installed and become easily dislodged and canted when installed incorrectly. You will be able to recognize the problem by inspecting each seals for any strange flat spots that look like the plastic grommet slipped to one side and got squashed. Replace all three when time permits. After everything is reattached and tightened down with no added sealant or lubricant... start the vehicle and assess all of the electrical things that misbehaved prior to this clean up.

Thanks for your quick response. I just read BMonkeys similar problem and his was that connector. Mine has sat for 5 days and when I started it, everything worked. I will do exactly like you suggested. I have some cleaner and will be very careful with it. I will post what happens with this.

 

[mrrsm]

Cool Beenz... As for the USB Power Adapters... the connecting power from the battery is an immediate and direct dump of DC power that would have little chance of affecting the PCM circuit when the engine is off. When running... the power draw would be next to nothing... but as you know... when the Alternator is not replenishing the battery... even a small Map Light can constantly worry a 12 Volt, 700 Cold Crank AMP Truck Battery to death with enough repeated drain downs.

My guess is that if you were close enough to almost feel a lightning bolt striking near the vehicle... the accompanying EMP it also generates (besides scaring the living sh*t out of you from the sudden flash of light and thunder) ...would be more than enough to fry a lot of electronic circuits... including the PCM and anything else digital inside the cab of the truck.

 

[JohnW]

Cool Beenz... As for the USB Power Adapters... the connecting power from the battery is an immediate and direct dump of DC power that would have little chance of affecting the PCM circuit when the engine is off. When running... the power draw would be next to nothing... but as you know... when the Alternator is not replenishing the battery... even a small Map Light can constantly worry a 12 Volt, 700 Cold Crank AMP Truck Battery to death with enough repeated drain downs.

My guess is that if you were close enough to almost feel a lightning bolt striking near the vehicle... the accompanying EMP it also generates (besides scaring the living sh*t out of you from the sudden flash of light and thunder) ...would be more than enough to fry a lot of electronic circuits... including the PCM and anything else digital inside the cab of the truck.

MRRSM Where do you get the pcm connector gaskets? Is that a dealer only item?

 

[mrrsm]

Unlike the ones for the GM PCM in the 5.3L Engines... all three of these 'non-metripac' style of Grommets are not readily available. However... call the dealership and use the GM part number for the C3 plug where the Grommet is in-dwelling that shows up in the upper left area of this attached image and see if they carry these as a set of three.

Other than that... only a Junk Yard Scavenger Hunt for some of these that might still be stuck up inside of the connectors they often cut off and discard during their tear downs of these SUVs will fill the bill. Its a dubious prospect that you will be finding them as over-the-counter items at other local parts places. Please remember that the Grommets are inside of the three cables ... NOT inside of the PCM:

 

[littleblazer]

Funny story on the power adapters, my mom's escalade somehow had the wrong fuse put in the power adapter slot and the little adapter actually killed the pcm fuse somehow. I however do not believe this is your problem. What you are describing could potentially be an ignition switch however I've never had mine go bad to know What it does.

 

[freddyboy61]

Would suggest a replacement of the ignition switch, since it's history is shakey and has been known to cause all kinds of strange electrical issures.