Picked up 98 Envoy one owner basket case today. Parked in 2012... Mice made there nest between VCM and heater. In the process they chewed through C4 RED and C3 WHITE harness's and nibbled at C1 & C2.
Get her towed home and scrub 4 years of alge and crud off. No rust or dents.
Put new battery and charger on her. Everything works except left rear shock has air & oil leak. Pulled compressor fuse out.
Body, wheels, tires, glass, bumpers are perfect. Interior what you expect for the mileage, 250,300km.
Both HID's work, however left takes 2 or 3 minutes to reach full output. Conversion to 9006 HID's in factory housing will match factory engineering design (GM used halogen 9006 bulb specs to engineer HID's not the EU specs that are todays standard).
SCFI to SEFI conversion and upper and lower gaskets done says owner.
Carfax & ICBC report no reportable accidents. Ran VIN through GM Canada no outstanding recalls.
Pics to follow

After 3 washes she looks good.
In fact better than expected!
Mice did a number on wiring...
Will get donor wiring later this week
Hope she runs well after all this work.
Before and after pics u guys might like.
For now still driving my 96 LT...

My Ole 96 LT and Envoy
Pic of where envoy sat for 4 years...
All that debries on the ground was on the roof and engine hood 10 inches deep.

 

Found 98 Blazer LT donor at auto wreckers with engine and tranny pulled.
Started removing harness from VCM. Looks like it terminates under engine bay fuse block. Working along firewall, freeing harness, loosing 4WAL and fuse block to get at connectors. Oh No!
Harness does not terminate at fuse block. It doubles back through firewall under dash. Its an un-yielding thick harness.
No way I want to try this in Envoy with engine and accessories in place!
Will cut 2 foot sections from VCM plugs C3(white) and C4(black). This gives me lots of room to make grafts at staggered lengths. Will temporarily twist wires together insulating with un heated shrink tubing...
Back at Envoy.
Have more problems. The wiring colour codes repeat themselves. Secondly the wiring was made in different batches as colour hue is off enough to make mistakes. So quite a bit on tracing with ohm meter to make sure circuits are correct.
Darn frustrating. Enough for today,
Hot wired fuel pump to pump old gas and water from fuel tank. Good news here 60 lbs pressure. Still at 45 lbs next day!

 

Thanks for moving post into correct section.

 

Plugged block heater in overnight. Nice and toasty!
Finished temporary wiring. Lets fire her up!
Ran fuel pump using pressure gage relief valve to purge any air.
Toped up engine oil and topped radiator off.
Turned engine over she tried to fire immediately but wouldn't start. Cranked for 30 seconds. Gave starter 5 minute rest and tried again. Exactly same scenario... Tried 3rd time, exactly the same.
Time to pull codes...
P0108 Manifold Absolute Pressure / Barometric Pressure Circuit High Input
P1106 Manifold Absolute Pressure Sensor Circuit Intermittent High Voltage
B1480 Battery Rundown Protection Circuit Malfunction
B2973 (Driver or Generic) Door Key Switch Circuit Low
B3102 Keyless Entry Data Link Circuit Low
U1255 Class 2 Communication Malfunction
U1301 Class 2 Communication Circuit Short to Battery
Another 2 or 3 hours of tracing circuits and reading schematics...
Turns out I mixed couple wires up...
Lets try again..
Envoy started instantly. Purring like a kitten!.
Shut her down and change oil & filter. Flush old coolant out and replace with 50/50 mix.
Air filter looks brand new. Same for Delco cap & rotor.
Tranny fluid smells burnt but no visually bad. on To Do list.
Start her up and take for test drive & fill tank. She drives great!
Get back home. Left rear brake hot, seized caliper, others just barely warm.
Radiator has leak on top front of left tank.
Drivers door needs pin & bushing set.
Only current code is P0147 O2 Sensor Heater Circuit (Bank 1 Sensor 3)
All the others have moved into history. What a relief.
Envoy is not a basket case anymore.

 

Glad to hear it runs as good as it looks. I hope that mouse got shocked when he chewed your wiring.

 

Glad to hear eveything worked out for you. After seeing the wiring chewed I wondered if they got under the dash. Did you find any nest. Their urine is so acidic not only does it smell it corrodes open electrical connections.

 

Thanks for your compliments and encouragement
Mice did not get into passenger compartment.
Nest was between left fender, firewall / heater and VCM.
They chewed through harness to make room.
Nest itself was very neat, lined with cedar tree leaves, grass and cloth.
Very comfortable and warm me thinks... They also had a patio on left side intake manifold / valve cover made out of same materials.
Sorry I ruined the resort plans.
Corrosion on the VCM is bad. Don't know best method for cleaning oxidation off and stopping further oxidation.
Speaking of oxidation the heater blower solid state variable speed controller is in same state as VCM. Spayed it with lacquer to hopefully seal it and slow down oxidation on aluminum heat sink.
Have terrible influenza. Managed to get drivers door upper and lower pin and bushings done. Taking a break. Have worked on her every day for 2 weeks.

 

Have problem with MIL dash lamp.
MIL lamp is dim about 25% brightness compared to rest of dash indictor lights.
Pinned C4 pin 5 to ground. No change in lamp brightness.
Even stranger, with C4 disconnected from VCM, MIL continues to glow at 25% brightness.
Reconnected C4 to VCM.
Hooked up Autoenginuity. it shows MIL is Off.
Only DTC is pending P0147. MIL not commanded on.
Commanded MIL on. Still Dash MIL still at 25%.
Okay... Must have wiring issue.
On C4 there are identical 2 BRN/WHT leads.
Pin 5 BRN/WHT is MIL.
Pin 22 BRN/WHT is Cruise Control Switch Input.
Unhooked my temporary connections revealing both native leads.
Lead from instrument cluster should show either 12 or 5 volts to ground.
It shows almost no voltage.
Checked VCM Pin 5 with Key Off Engine Off. No conductivity to ground.
Key On Engine Off = path to ground
Key On Engine Running = No conductivity.
Therefore VCM operating correctly.
Pin 22 shows 12 volt voltage ith Key On
Probe native BRN/WHT leads again. There is less than 1 ohm resistance between them! How is this possible?
Cruise Control functions correctly.
I'm not an electronics tech. Just a handy guy with hammer and bent nails...
Studying the schematics these leads are not connected. PIN 5 goes directly from VCM to A11 on cluster.
So either there is a short or I'm not understanding how this circuit works.
If anyone would probe with ohm meter C4 PIN's 5 and 22 and report on findings. I would appreciate it.

 

Wiring resolved!
Turns out there are 3 identical brown w/ white stripe wires. 2 of the 3 only used in 1998! Not really sure what they do (they are conected to cruise control) but tried connecting them and reversing connections, but did not make any difference...
Had 1 of the 3 mixed with MIL indicator circuit also a brown w/ white stripe.
Only thing left to fix is air leveling system. Re & re compressor cleaned out compressor valves and tested to 75 lbs. Don't know what max pressure should be?
Leveling valve next project...

 

Leveling valve is good.
Plug was out about 3/16" and full of road grime.
Cleaned contacts up and seated plug.
Turned ignition on pump started.
After 20 seconds suspension raised about 1 inch then pump shut off.
Small leak as pump cycles for 5 - 6 seconds every 10 minutes.
Other than that rear suspension works well, holding height no matter how much weight is loaded in.
Disassembled compressor and cleaned / polished valve seat surfaces. Not impressed with design of nylon exhaust valve. Couldn't get electric exhaust valve apart without damaging it. Re-routed air intake from wheel well to inside vehicle.
Instead of using standard air leveling valve and standard compressor & reservoir. GM opted for electric leveling controls.
It works by leveling valve signaling compressor to start to increase height.
When desired height is reached leveling valve shuts pump off.
When suspension is too high leveling valve signals electric valve in compressor head to release pressure until correct height reached and valve closes.
Too many places for air to leak. System depends desiccant cartridge seal, perfect piston / cylinder seal, exhaust valve seal, intake valve seal, electric exhaust valve seal and several push on air connections.