Octania

Wife complains that the blower shuts off for no reason
Similar thread here and other info points to blower resistor

Fancy digital display dual-zone computerized bullsnort type system.
[oh for the simple days of yore]
[this is 7 yrs old; Dodge HVAC illumination died at ~6 yrs old, the actual solution was not to replace the bulbs... but to replace the entire $125 control head assembly. Seriously. Meanwhile I have FIFTY year old Oldsmobiles with bulbs that still work, and if need be, can be replaced. ]

I did find this

"There are 4 fuses in the system to verify first.
The blower fuse in the underhood fuse box (40 amp, fuse #35)
The HVAC fuse in the rear fuse block (30 amp, fuse #44)
HVAC I fuse in the rear fuse block (10amp, fuse #39)
HVAC B fuse in the rear fuse block( 10 amp, fuse #36)

If the fuses all check out OK, go to the blower motor and check for power on the purple wire, key on, heater on. If it has power, check that the black ground wire is grounded.
If power and ground there, replace the motor assembly.

If no power there, go to the resistor block beside the blower motor.
Set switch to high fan. Check for power on orange and red wire on resistor.
If power there, replace resistor."

and this $55 new controller

70-442-W30

Judging by the number of reviews on Amazon, I'd say that is a pretty common failure.

Octania

Plus the part where this 7 yr old car already has had a new one intalled due to GM's use of inadequate terminals for the amperage the blower motor draws. I swear they don't retain lessons learned from the past.

The resistor/ controller in place now is plastic body, and was evidently installed wrong way around to boot. Ordered newer better?? one last night, if that doesn't do it, we'll try the next suspect. Try to catch it misbehaving. OF course, while I had the meter out handy and the panel off, everything worked perfectly.

70-442-W30

I had to change the resistor for the Expedition I had. Front blower motor wasn't working but the rear was. This went out when we were at the beach and it was 90+ degree weather. Went to Dollar General, bought a cheap household fan and used it to circulate air to the front. Can't remember for sure, but I think my cost was around $65, plus some contortionist damage to my neck to get under the dash.

Railguy

Mine only worked on high . I giggled the connector now it works must have been not making good contact. Did you try that?
Railguy

Octania

OH I giggled it real good while it was out.

Another resistor/ controller on the way, then troubleshooting by wire color.

ps their other favorite fail mode is to fail in ON mode, and even if ign sw is OFF the fan continues. What a failfest. We need to stop this computerized bullshit and go back to "just enough" electronics.

I see an opportunity, retrofitting by removing over-complicated crap and installing robust stuff that is simple, lasts, and is easy to diagnose and fix.

Railguy

I was saying to friend just the other day if you took all this crap and through it in a pile how much would it weigh?
Railguy

Octania

enough to get the average mpg up to 12 maybe?

That's pretty bad. I had 425 powered 4000 lb Olds and the like that did better than that. With points. And a carb. 50 yrs ago. So other than the failure prone electronics, where's the advancement? better plastic wood on the dash I guess. ABS Disk brakes.

Octania

The new "resistor" which is evidently an electronic controller arrived today. It took a 10m drive to get the existing unit to misbehave again. The plug mathces the new part, and when I plugged in the new unit, HIGH worked like it should.

So I put in the new part, right way 'round. Metal case. Delivered in a day or so, dirt cheap via Amazon Prime.

Evidently per internet search, one of this thing's favorite fail modes is to leave the fan on at all times, even with the vehicle off and the key removed. No, not the 10m shutdown radio grace period,. Forever. Until the battery runs out.

Ozzie

I'm getting increased appreciation of your views as time goes on.

allyolds68

Wait until you have to replace the clutch fan. That's electronic too.


When that happens let me know. You don't have to disassemble the entire front end to get it out like the repair manual says.


Any yeah, the gas mileage absolutely sucks on Envoys. We got rid of our 02 four years ago. Like most cars today, lots of stupid stuff like this starts to go wrong after 75k miles.

Railguy

My 2nd car was used 73 vega.It was a piece of junk .A piece of junk, it got over 30 MPG.
railguy