What system should I inspect first for the following issues on a 2004 Chevy Aveo?

Question

A 2004 Chevy aveo with around 78,000 miles has the following issues:

The Daytime Running Light indicator (as well as the lights themselves) randomly turn on and off. This is a slow thing and has never happened rapidly. It usually happens after five to ten minutes. This doesn't affect using the lights as normal if they are manually enabled.

When the gas light should turn on, instead the check engine light turns on. No gas light ever comes on.

Occasionally when the car is started the HVAC fan doesn't work and won't start at all. Turning the fan level from 3 to 4 (it's highest setting) creates an audible click that seems to be coming from behind the steering wheel. This happens while the fan is working, but I decided to include it for completeness.

I've included all of the symptoms here because this seems to me like they might be from a shared electrical issue, however, my experience is mostly in computer repair.

Is it possible for these symptoms to stem from the same issue? If so, which system should I investigate first and what should I look for?

Answer 1

The first thing to check are the grounds anytime you have seemingly unrelated systems not working, working sporadically, or as I like to call it, any time you have gremlins running around in the electrical system.

Looking at the ground distribution for G202 pictured below you can see that Instrument panel cluster, and the daytime running lamp module share the same ground and are connected through what I think is a splice connector SP202. The splice connector and G202 is the first place to inspect for a loose or corroded connection.

The blower motor also share that same ground, not sure why it's not on the diagram above though.

What I am not sure of is where G202 is, I can tell you it's under the dash based on the numbering system GM uses. 100s are in the engine compartment, 200s are between the A and B post, 300s are between the C and D posts, 400s in the trunk.

I would start out tracing the ground wire from the blower motor as that is most likely the easiest to follow.

Answer 2

Potential exists for the problem to be in the alternator voltage regulator. I've noted Mitsubishis often have really random dash light behavior when the voltage regulator starts going out (especially if the voltage swings to the high side, like anything over 15 volts).