[Fixedit]

2002 accent 1.6 auto.
Recently got this car despite certain problems. The engine runs well and it mostly works well.
But the AC will shut off and quit blowing as soon as I turn on the headlights.
But, when i turn off the lights, i can restart the AC and it starts blowing again.
I haven't isolated if the AC itself shuts off, but the fan certainly does.
On other days the same problem happens at random times during driving, and it takes a few minutes before a successful restart of the blower.
I replaced the blower motor resistor today, and it fixed nothing.
So what's going on here?
Is it a relay? Blower motor? Electrical problems elsewhere? I'm stuck

 

[Fixedit]

Update
I've tested for power at the blower motor, and everything is peachy until the lights get turned on. Then it's dead. It's basically like the lights completely switch all acces to power off to the blower and use it themselves. The compressor also turns off when I'm using it. But the blower can be on without the ac on, and it will have the same symptoms.
I replaced the blower motor relay, just in case, and it turns out the new one doesn't work at all, so i put the old one back in, and it's back to its normal brokenness.
Checked all related fuses, and there's no problems.
I'm guessing there's some sort of short in the wires, but how is it possible to consistently work like this?
Could it be in control switch?
I guess it's possible that the lights ground out the power to the fan, but then fuses would be blown... right?

 

[AUTOSPARK]

I guess it's possible that the lights ground out the power to the fan, but then fuses would be blown... right?

Right.

What I suggest is you remove the blower relay from the engine bay fusebox and carry out a bypass test by bridging the larger two of the terminals on the relay socket using a short link wire...see below. Check to see if the blower is now able to operate while the headlamps are switched on. That should at least give you a clue about where in the circuit the fault lies. Is it a fault on the control side of the blower relay, or the load side.

If I helped you fix it, why not...

Your support is greatly appreciated​

 

[Fixedit]

Thanks Autospark
I've jumped the 2 larger blades and it worked like normal.
So what does that mean? Do i try another relay?
Am I gonna start a fire if i leave it jumped and continue to use it?

 

[AUTOSPARK]

So what does that mean? Do i try another relay?

You just bypassed the load side of the relay and everything works. So that must mean the problem is on the blower relay control circuit.
I suspect the problem will be somewhere on the car, so another relay is unlikely to help.

What I would do now is test the relay control terminals on the socket (the smaller two) with a voltmeter to try and figure out which side of the circuit is dropping out when you switch the head lamps on :
Remove the blower relay from the fusebox.
Turn the blower switch on.
Switch the ignition on.
Connect the black meter probe to battery negative.
Touch the red meter probe to each of the smaller terminals on the relay socket. You should get 12V on one of them.
Now switch on the headlamps and probe the 12V terminal again. Is the 12V still there or has it dropped to a much lower voltage?
If the voltage has dropped you now know the problem is on the relay control power supply circuit.

If the 12V remains after the headlamps are switched on :
Switch the headlamps back off.
Leave the ignition and the blower switch on.
Connect the red meter probe to battery positive.
Touch the black probe to the other small terminal of the relay socket.
You should get 12V again.
Now switch the headlamps back on. Is the 12V still there or has it dropped to a much lower voltage?
If the voltage in this test has dropped you know the problem is on the relay control ground circuit.

Let me know what you find and we can decide where to look next.

If I helped you fix it, why not...

Your support is greatly appreciated​

 

[Fixedit]

Ok, so i ran that test, and it's the positive, not the ground enough the headlights affect. The voltage drops to near zero when I switch them on.
Where do i look next?

 

[AUTOSPARK]

Ok, so i ran that test, and it's the positive...Where do i look next?

The RAD FAN relay.

Basically the same test again. Switch the ignition on and measure the voltage on the two blue terminals on the diagram below. One should have 12V.
If that checks out OK, switch the headlamps on and recheck. Is the 12V still there or has it dropped like the blower relay did?

If I helped you fix it, why not...

Your support is greatly appreciated​

 

[Fixedit]

12v stays there. Unaffected

 

[AUTOSPARK]

OK, I think that points to a problem on the engine bay fusebox in that case.
At the side of the fusebox there is a junction block (see below) that links all the relay coil power supplies together. The power supplies for the blower relay coil and the rad fan relay coil come from that junction. That would seem like the most likely place for a problem to develop. We know the circuit upstream of the junction must be OK because the power supply to the rad fan relay was uneffected by the headlamps. What I would do now is unbolt the fusebox so you can access the junction, then unclip the top cover and check for signs of water ingress/corrosion.

If I helped you fix it, why not...

Your support is greatly appreciated​

 

[Fixedit]

i don't see any problem there, but i also don't know what would look like a problem there.

 

[Fixedit]

I've discovered that this driver's side fender has been removed (whether replaced or just for doing the primer, I'm not sure. But I've noticed that the wheel well guard is missing, and there's about 100 wires unprotected, several of which have been spliced. There's one live (always on with ignition) hot wire that's just hanging.
So im guessing my problem is in that area... any specific wires to look for?

 

[AUTOSPARK]

Seems cars in the US are wired a little differently to ours here in the UK. As you can see below, on UK/European models the blower relay coil is supplied with power via E48 terminal 1. But your car doesn't have a link bar (the brass parts in your photo) in terminal 1.

any specific wires to look for?

According to the diagram above the ignition power supply that powers the blower relay coil is a blue wire with black stripe. That wire also powers the front wiper relay coil too. Do your wiper arms self park when you switch the wipers off? Does the intermittent wiper work OK?

If I helped you fix it, why not...

Your support is greatly appreciated​

 

[Fixedit]

Yes the wipers seem to work fine, although i haven't tested them with the lights on.

 

[AUTOSPARK]

Maybe try repeating the voltage test on the wiper relay to see if the voltage on that one drops when the headlamps are on.
Also, since you have the fusebox off now anyway you might be able to unclip the cover from the bottom and check the blower relay power supply wire inside the box. Follow the wire and see if you can find where it connects to that blue/black wire and see if there is any green crud on the splice connection.

If I helped you fix it, why not...

Your support is greatly appreciated​

 

[Fixedit]

Well somehow i fixed it. I traced the blue/ black wire All the way from the relay to the firewall, but right as it turned the corner behind the battery i found a split with the extra wire running back to the relay box into the horn relay (which is missing). Then i remembered how the horn had the same affect as the headlights on the blower.
I tested the voltage on everything, and the horn at the relay was 7. The blue/ black wire was the same. The aforementioned hanging loose wire was a firm 12. So i figured that the loose wire was supposed to be in the same line and connected it all together, and presto.
Also found some weird unused connectors and loose wires under my dash, and just ensured they weren't shorting anywhere.
Anyway, thank you AUTOSPARK very much for your help. The blue/black thing was key.

 

[AUTOSPARK]

thank you AUTOSPARK very much for your help. The blue/black thing was key.

Diagnosing faults on these older cars gets quite challenging with all the wiring modifications folk make over the years. Anyway, great to hear you figured it out and I'm happy I was able to at least point you in the right direction.

If I helped you fix it, why not...

Your support is greatly appreciated​