electrical or???

[frogman]

Sunday, no headlights at night, high beams, flash to pass all worked
fine. Thought low beams were blown.
Monday am, everything worked. Puzzled. Went to Chevy, Advanced Auto, then
auto electric (mechanic) He switched relays.
Left the shop, went one block, low beams out, hi beams out, flash to pass
ok. Went to fill tank and returned to shop. Stopped at red light, low
beams on. Hi beams worked. Flash to pass, working. The only thing I
noticed was that the manual over ride light switch has a small light
that indicates that the sensor in the dash that lets the tail lights come
on in cloudy weather or after dark was on. It was middle of the day, no
clouds. I hope that makes sense.
Mechanic wants me to leave the car there. Says if he can duplicate the
problem, he can run some diagnostics to see what's going on.

Side note, which does not present a real problem, but could be related:
rear wiper works when it wants to. Washer in dash is very noisy. 2nd
speed on fan switch works after it has been on a while. 1 and 3 are fine.
After I run the fan on 1 or 3 for a while, I can switch to 2 and it will
work. Starting with 2, fan does not work.
The directional for the a/c or heat clicks if I try to turn it to the
floor or defroster. After 152000 miles, I'm sure it's just work gears.
Just throwing it in.

I'm scheduled at the mechanic Thursday am. I see a big bill looming. The
relay switch alone was going to be $106.00. Any help or suggestions, I
would appreciate it.

 

[Wooluf1952]

Welcome, Glad you made it over.

In case you haven't heard:
http://gmtnation.com/f5/welcome-gmtnation-com-heres-story-226/

The relays for #45 and #46 are under $40 from most auto parts stores.

Do you have the manual or electronic HVAC?

 

[frogman]

Welcome, Glad you made it over.

In case you haven't heard:
http://gmtnation.com/f5/welcome-gmtnation-com-heres-story-226/

The relays for #45 and #46 are under $40 from most auto parts stores.

Do you have the manual or electronic HVAC?

I'm guessing manual. Not sure what the difference is. But if it cost more to get it new, I don't have it! LOL
Seriously, I have two t-stat sliders, fan switch, directional switch.

P.S. Thanks for inviting me! Great site!

 

[Sparky]

Yup that would be manual. Auto would have a digital readout.

I can't speak for all the issues but the ones I'm pretty sure on:

Fan speed issue is probably the fan resistor unit. Most common thing to act up. Mine for example lost 1 entirely, the rest worked fine. It is under the dash on the passenger side, takes like 10 min if you're taking your time.

The clicking does sound like one of the actuators to me. Those are fun to get to

 

[The_Roadie]

Welcome! Boy, you sure have a list of stuff going on.

The HVAC system with discrete fan speeds 0-5 is the manual system. Many of them have a problem with the resistor pack and the connector that feeds it. You lose one speed at a time until it's totally dead. Click here for an article how to locate and change the parts: http://gmtnation.com/f93/how-replace-blower-motor-resistor-pack-connector-pigtail-3004/

Rear wiper is often flexed and broken wires in the liftgate hinge area, protected by a rubber boot from everything except flexing, which can break the copper conductors inside the wire insulation.

Airflow mode actuators go bad all the time. Run a search on the phrase "mode actuator replacement" and/or check out this thread: http://gmtnation.com/f23/2002-envoy-mode-door-actuator-replacement-2787/

Low beam relays also fail a lot - exchange the one for your fan clutch (45 and 46) as an experiment.

 

[frogman]

Welcome! Boy, you sure have a list of stuff going on.

The HVAC system with discrete fan speeds 0-5 is the manual system. Many of them have a problem with the resistor pack and the connector that feeds it. You lose one speed at a time until it's totally dead. Click here for an article how to locate and change the parts: http://gmtnation.com/f93/how-replace-blower-motor-resistor-pack-connector-pigtail-3004/

Rear wiper is often flexed and broken wires in the liftgate hinge area, protected by a rubber boot from everything except flexing, which can break the copper conductors inside the wire insulation.

Airflow mode actuators go bad all the time. Run a search on the phrase "mode actuator replacement" and/or check out this thread: http://gmtnation.com/f23/2002-envoy-mode-door-actuator-replacement-2787/

Low beam relays also fail a lot - exchange the one for your fan clutch (45 and 46) as an experiment.

Mechanic already switched relays. Not the problem. Thought the night time sensor might be related, but that also proved false. Not looking forward to replacing the actuators, but will do eventually when I have the time. I rewired the wiring harness in the lift gate twice. No improvement in the rear wiper timing.
Thanks for the help articles. I will definitely use them. Replaced transmission shift cable with the helpful articles. But, this lighting issue has got me stumped.