Montero SR head unit?

[icant4x4heretoo]

Very clear wiring schematic in the back of the factory service manual. Download it free at www.mitsubishilinks.com

been there along time ago, I DL these 2 since I have 1999 SR. I did not see it any where, may have missed but what section and page was it on?
montero_fsm_1998_vol1_engine-trans-fuel
montero_fsm_1998_vol2_body-axles-electrical

 

[legerspencer]

your problem is that you bought a 4 ohms speakers and these rigs run 6 ohms...im back at this problem as the PO of this had a aftermarket unit and speakers but its trash now and ever thing looks so odd to me...4 wires to a speaker? oh i can't find speaker diagram for it too....any one? I just plan on wiring straight to the head unit to each speakers... 4 speakers is good enough for me.

You sure ohms matter since I'm using an aftermarket head unit and not the original?

Also, my alternator just went out and I'm wondering if that has any relationship with my speakers shutting off. It could be completely coincidence, but I wonder if my Montero shut off power to the amp when it realized I was losing power. My dash lights started dimming so it makes me question if it would cut power to the amp. Anyone have an idea?

 

[PacS14]

You sure ohms matter since I'm using an aftermarket head unit and not the original?

Also, my alternator just went out and I'm wondering if that has any relationship with my speakers shutting off. It could be completely coincidence, but I wonder if my Montero shut off power to the amp when it realized I was losing power. My dash lights started dimming so it makes me question if it would cut power to the amp. Anyone have an idea?

My 99 did something similar when my alternator died and was running just on the battery, radio stopped working, then windows, not immediately since I have a red top battery, but sure enough at first I thought it was a fuse and it took nearly a week (short drives mainly) to realize my truck would not stay running and the battery was drained.

 

[legerspencer]

Replaced the alternator but the speakers still cut off with the head unit running. Tonight I only drove for 20 minutes before the speakers cut out completely. Any ideas why it works for a little bit then cuts off? Fuses? The speaker ohms? Amp issues?

 

[legerspencer]

Replaced the alternator but the speakers still cut off with the head unit running. Tonight I only drove for 20 minutes before the speakers cut out completely. Any ideas why it works for a little bit then cuts off? Fuses? The speaker ohms? Amp issues?

 

[Salonika]

If the speaker ohms aren’t matched to the head unit you are probably tripping some type of thermal protection.

 

[legerspencer]

The factory premium sound speakers are 3 ohms (except the tweeters on Gen 2.5 sail panels, which are 4 ohms and have a ~14khz HPF anyway), running a 4 ohm aftermarket speaker is fine that's asking the amplifier for less current to drive them. It's easier on the amplifier.

But if you're using the factory amplifier and driving it with output from an aftermarket head unit that's the likely cause of your problem. The factory amp is looking for a balanced low voltage (~1Vrms) signal because that's what the factory head unit supplied and with an aftermarket head unit wired in you're either delivering a 6V DC offset and ~6-7Vrms balanced or you're supplying an unbalanced 2-6Vrms signal depending how it was wired in.

The best thing you can do is take the factory amp and throw it in the trash, along with any lower dash speaker you may have in there. The factory amp doesn't have a DC-DC power supply, its rails are the exact same offset ~0-12V that any aftermarket head unit uses so the minute you install an aftermarket head unit and aftermarket speakers, the relevance of the factory amp drops to zero. The power amp output devices - if you're curious - are TA8233H BTL units that pretty much lose their composure over 10W regardless of what impedance the load is, they are rated to operate at 2 ohms and can deliver 30W per channel into that impedance at 10%thd (yuck!)

Wow. Some of the stuff you said just went over my head, but thank you! Looks like I have some learning to do, and I'll put bypassing the factory amp on my list. That should solve this issue correct?

Until then, is there anything I can do to help prevent my speakers going out?