Hi guys. Been a while since I've posted in here. Used to frequent this place a lot. But thankfully I haven't really had a major problem with the car in a few years, its been that reliable. But this one I've got now has really stumped me.

It started when I was not able to start the car at all. Car wouldn't turn over, no firing sounds, no lights, no central locking, no trip computer, completely dead. Battery and alternator was tested. Completely fine. An hour later the car magically starts. About 30 mins into my drive i notice the aircon controls are unresponsive and the aircon display is displaying "communication error" where the air flow and temp is normally located (not to be confused with the comm error for the radio display). So I thought "crap that's what's happened, my air con has shorted somehow and tripped some safety and that was why my car wasn't starting".

About 30 minutes later into the drive im changing the volume on the custom double din headunit I have in there that's been in there for 3 years running without fault. As I increase the volume and let go of the button, it keeps increasing to the point where it's at max volume and absolutely blowing my ear drums out. Nearly lost control of the car. I force shutdown the headunit. Turned it back on. Was still blaring and all the headunit controls were unresponsive. So I was forced to shut it down again. The second time i tried to turn it on it would not turn on at all. So now both the headunit AND aircon controls are unresponsive and displaying communication error.

I've checked accessories fuse, aircon fuse, and all other related fuses. Pulled apart centre console and visually inspected cabling. I'm no electrician but everything looked in tact. I made sure the ground wire for the headunit was screwed in tight. As I said the battery is fine. Only a few months old and in perfect condition. Alternator was giving back good readings. Literally everything else electrical works normally except the aircon and headunit.

Does anyone know if the aircon and headunit are on the same circuit? Anyone possible clues to what the issue is? I've read somewhere that the 380 has a separate ECU for the aircon. Is this true? Help me forum!

EDIT: Also forgot to note, the headunit will rarely come back on by itself upon start up of the car (as it should) but the controls on it are still unresponsive as are the aircon controls.

I think you might be having intermittent voltage regulator problems. How long did your last battery last?

If the alternator is overvolting intermittently it could cause the problems you describe, and could be what fried your old battery.

I think you might be having intermittent voltage regulator problems. How long did your last battery last?

If the alternator is overvolting intermittently it could cause the problems you describe, and could be what fried your old battery.

As I said the alternator tested fine, but I guess if it's intermittent it could be hard to detect unless looking for it initially. It tested fine the last time the battery was replaced also. I can't remember how long it lasted, but was at least a few years.

And just another update. The headunit, as I said, will sometimes power on on car startup, but the volume control buttons do not work. The touch screen will work and the power on/of button. Also, when the headunit powers on, the AC controls are still unresponsive. Don't know exactly what this means, but it's a consistent qwerk that I can identify.

Also something to keep in mind. Not only are the AC controls not working, but the AC display is displaying a "communication error" to the actual AC unit.

EDIT: Just had a thought. If it was an intermittent voltage regulator problem, would it not be affecting more than the aircon and headunit system specifically? Shouldn't I be getting all kinds of intermittent electrical faults then? It feels like there is a voltage issue on the specific circuit that the AC and headunit are connecting to (i'm assuming they are on the same circuit, correct me if I'm wrong). I don't know if that necessarily means it's an issue with the voltage regulator. Obviously I'm not an electrician in any sense of the word so I'm purely tackling this from a "logical" perspective.

I had a similar thing with my KW. Driving along and battery light starts to flicker, radio cuts in and out, A/C cuts in and out and once at night, low beam became so bright that on coming drivers were yelling at me. It turned out to be a faulty voltage regulator. The 380 has CAN BUS so the behaviour may be a little different. I suggest you hook up a long wire onto the battery terminals and drag into the cabin and hook up to a multimeter. Drive it till the symptom appears and see what the reading is. That is what I did and found it was spiking.

I had a similar thing with my KW. Driving along and battery light starts to flicker, radio cuts in and out, A/C cuts in and out and once at night, low beam became so bright that on coming drivers were yelling at me. It turned out to be a faulty voltage regulator. The 380 has CAN BUS so the behaviour may be a little different. I suggest you hook up a long wire onto the battery terminals and drag into the cabin and hook up to a multimeter. Drive it till the symptom appears and see what the reading is. That is what I did and found it was spiking.

Sigh... I knew this would happen. I'm not meaning to be rude here, but I've already addressed everything you just said. My issue is not really like yours at all. Battery light never came on. The battery and alternator was tested as fine. The issues are not intermittent while driving. I only said that the HEADUNIT will intermittently power on upon startup. Usually there is just no power at all to both headunit and AC controls. As I said, if it was a voltage regulator issue, why would it be only affecting the AC and headunit? Not various things randomly, like in your example.

In my case there is no flickering of anything, it's basically just no power going out. Literally everything else electrical in the car works fine.

I rang an auto-electrician and he was pretty certain it was just a blown fuse. So when I get the chance I'm literally going to check every single fuse (ive already checked the ones I thought relevant) and replace any broken ones if I find them. If that still doesn't work I'm going to have to take it in to the auto elec and get them to have a squiz.

Hmm, OK, how did you check the fuse (as from your previous posts you ruled out fuses)? Fuses do not have to show physical separation for them to fail.

Don't sigh, because people are trying to help on a free forum.

I and many other forum members have had a battery and alternator test fine, and it's turned out to be the culprit after all. That's why people are suggesting it gets another look. It could be that the aircon ECU won't deliver power to the centre console area if it detects a voltage issue (under or over voltage).

Turn the car to the ON position without starting it. Do the radio and aircon controls (ie cabin fan etc) work normally? The only part which won't work with the engine off will be the light indicating the the aircon is working (as the compressor is stopped).

If the fault still exists, then remove all the fuses one by one and test them with a multimeter for continuity. Some fuses look okay when they have in fact failed.

Hmm, OK, how did you check the fuse (as from your previous posts you ruled out fuses)? Fuses do not have to show physical separation for them to fail.

I only checked the fuses for physical breaks, as I wasn't aware at the time that a fuse could fault without it. As I said, I'm going to go back and test every fuse manually with a multimeter and see what i find.

Don't sigh, because people are trying to help on a free forum.

As I said, not trying to be rude. Just being honest. It's frustrating when you think you stated something clearly and people either misread it or misunderstand it. Especially with these kind of frustrating issues. I just got off talking to a group of friends asking me stupid questions for half an hour like "did you drive through a lake" so I wasn't in the mood.


I and many other forum members have had a battery and alternator test fine, and it's turned out to be the culprit after all. That's why people are suggesting it gets another look. It could be that the aircon ECU won't deliver power to the centre console area if it detects a voltage issue (under or over voltage).

I understand that, but the car was already tested at length while running. vlad suggested running a multimeter while driving, which is not relevant really to my issue at all, as there is no "spike" or intermittent power on/off. It just remains off with the headunit powering on at startup rarely, and it will actually stay on unless I turn it off. And again, if it was a general voltage issue as you claim, the aircon ECU wouldn't be the only thing affected by it, would it not? I've not had a response addressing that yet. I've seen voltage regulation issues in my cars before and they are never this specific.


Turn the car to the ON position without starting it. Do the radio and aircon controls (ie cabin fan etc) work normally? The only part which won't work with the engine off will be the light indicating the the aircon is working (as the compressor is stopped).

When the car is in ON position neither the radio nor aircon controls work at all. As mentioned. If the headlights are on the buttons will backlight, but the controls are completely unresponsive.


If the fault still exists, then remove all the fuses one by one and test them with a multimeter for continuity. Some fuses look okay when they have in fact failed.

Yep will do so. As mentioned.

Check the fuses using a multimeter for continuity.

For the A/C:
Check fuses 10, 20 and 22 in the relay box and fuses 2 and 16 in the junction box.

For the audio system:
Check fuses 20, 22 and 23 in the relay box.

If both the A/C and audio system are acting up, then it could be a faulty 20 and or 22 fuse.

Check the fuses using a multimeter for continuity.

For the A/C:
Check fuses 10, 20 and 22 in the relay box and fuses 2 and 16 in the junction box.

For the audio system:
Check fuses 20, 22 and 23 in the relay box.

If both the A/C and audio system are acting up, then it could be a faulty 20 and or 22 fuse.

Thanks man. If I don't find any continuity issue with any of those is it worth still checking every other fuse just in case? Also all those fuses are in the in-cabin fuse box yes? Not the engine compartment one?

Thanks man. If I don't find any continuity issue with any of those is it worth still checking every other fuse just in case? Also all those fuses are in the in-cabin fuse box yes? Not the engine compartment one?

Yes the relay box fuses are in the engine compartment. Note that fuse 10 is for the A/C compressor and A/C ECU but 20 and 22 are muti-purpose ones.

Fuse 20:
A/C-ECU, A/T selector lever position illumination lamp, combination meter, fog lamp switch, headlamp (RH), glove box lamp, hazard warning lamp switch, multi-center display unit, radio, CD player, rear combination lamp (RH), rheostat and TCL switch

Fuse 22:
A/C-ECU, column switch, combination meter, ETACS-ECU, front-ECU, key reminder switch, multicenter display unit, radio, CD player, and vanity mirror lamp

Fuse 23:
A/C-ECU, accessory socket relay, ETACS-ECU, multi-center display unit, radio, CD player.

Fuse 2 in the centralised junction (passenger compartment) is for the blower motor and resistor

Fuse 16 in the centralised junction (passenger compartment) is another multi-purpose one:
A/C compressor clutch relay, A/C-ECU, blower relay, condenser fan motor, fan control relay, front-ECU, outside/inside air selection damper control motor and rear window defogger relay

Yes the relay box fuses are in the engine compartment. Note that fuse 10 is for the A/C compressor and A/C ECU but 20 and 22 are muti-purpose ones.

Fuse 20:
A/C-ECU, A/T selector lever position illumination lamp, combination meter, fog lamp switch, headlamp (RH), glove box lamp, hazard warning lamp switch, multi-center display unit, radio, CD player, rear combination lamp (RH), rheostat and TCL switch

Fuse 22:
A/C-ECU, column switch, combination meter, ETACS-ECU, front-ECU, key reminder switch, multicenter display unit, radio, CD player, and vanity mirror lamp

Fuse 23:
A/C-ECU, accessory socket relay, ETACS-ECU, multi-center display unit, radio, CD player.

Fuse 2 in the centralised junction (passenger compartment) is for the blower motor and resistor

Fuse 16 in the centralised junction (passenger compartment) is another multi-purpose one:
A/C compressor clutch relay, A/C-ECU, blower relay, condenser fan motor, fan control relay, front-ECU, outside/inside air selection damper control motor and rear window defogger relay

Tested 23 and 2 and both were fine. 20 and 22 where in this weird bracket that locked them into place. It was plugged so you could only pull it out to a point to disconnect them, but not all the way out of the box. Not sure why that is. Fuse 16 was non existent in the cabin fuse box. The port for it was there but there was no fuse, and there never has been. Is that weird? Anyway, at this point i'm completely stumped. I'm convinced it's a loose or faulty wire. I turned the car sharply while the headunit was on and the volume suddenly started going up continuously and it only stopped once i manually shut it down. This scenario happened twice today.

Prob going to take it into auto elec tomorrow.

20 and 22 are special fuseable links. There is a way to remove them. You will have to remove the bracket first. As for 16, is yours climate controlled or standard A/C? I remember the L and W series magnas had the cut down climate control whereas the Veradas had the full climate control. Don't know whether the 380s are the same.

As for the volume change, that reminded me of my old KS V6XI that would cut audio when doing sharp right turns. Opened the dash up and cable tied every loom and it still did it. I reckon it is a lose solder inside the unit.

Have you PMed or called madmagna?

20 and 22 are special fuseable links. There is a way to remove them. You will have to remove the bracket first. As for 16, is yours climate controlled or standard A/C? I remember the L and W series magnas had the cut down climate control whereas the Veradas had the full climate control. Don't know whether the 380s are the same.

I don't think mine is climate control? It has auto temparature. Don't know if that's the same thing.


As for the volume change, that reminded me of my old KS V6XI that would cut audio when doing sharp right turns. Opened the dash up and cable tied every loom and it still did it. I reckon it is a lose solder inside the unit.

Have you PMed or called madmagna?

I took it to the auto elec this morning and after looking at it for 5 minutes he said it's probably something to do with the BCM and told me to take it straight to mitsubishi for a report (which I was going to do in the first place but was deterred from by friends!). He said he'll then look at the report and see if he can do anything. He said it's a mitsubishi 380 specific problem and he couldn't diagnose the fault in the BCM with industry standard tools as they are so specific to the car.

Hmm, I suggest you give Mal aka madmagna (mitsi-fix) a call or a visit before going to the dealer.

Hmm, I suggest you give Mal aka madmagna (mitsi-fix) a call or a visit before going to the dealer.

I'll call him and see what he says. The only issue is he's 1hr away from me, and the mitsi service center is walking distance from my house. Hopefully it's worth the drive and not too expensive a fix.

Not sure if the BCM needs replacing or reprogramming though. Does Mal do auto elec work? I thought he just did services and parts?

Hi all. Just an update. Finally managed to get the car in last night to Mits-Fix to have a look. They are looking it at it now, but I just got off the phone with one of the guys there. It's a VERY rare issue they've only seen one other time with someone who had almost the exact same issue as me. They think it has something to do with the headunit's connection to the steering wheel controls (which haven't actually worked at all now for 1-2 years) having an effect on the computer. The said the 380 computers are a sort of very closed system and it doesn't "like" aftermarket things tapping into that. And in the case of the other guy, they had to disconnect the steering wheel controls entirely and replace the whole ECU/BCM block. I won't really miss not having steering wheel control of the headunit if that indeed ends up being the issue, as, as i mentioned, they hadn't been working for a while anyway. Although ironically I was going to ask them if they could have a look at why the controls weren't working as a side note originally. lol

The weird thing is I've seen a lot of successful headunit installs on here that work fine with steering wheel control integration. Admittedly my issues with it started 1-2 years in. So I wonder if many others on here that have done the same thing have ever experienced anything like this after integration, or perhaps they yet will. Maybe it's something specific with how MY headunit interacts with the controls (Sony XAV-701bt), i have no idea.

But just thought I'd update the thread for the record and in case anyone else has a similar problem down the line and comes across this. I'll post an update once I get the call from the guys today with news of what they've found.