I recently bought a 94 Toy Landcruiser with a Kenwood DPX-MP4030 head unit. Sometimes the stereo works and sometimes it doesn't. It will come on and off in the middle of driving or even when parked. The frustrating thing is that the cd player will still eject disks so I know there is power to the head unit even though there is no indication of it from the display!
I took apart the dash and found a dead mouse on top of the stereo (nice!) and chewed harness wires! I spliced in new wires and disassembled and cleaned the head unit but to my dismay, the stereo still only works intermitently. I checked the groud with test leads while the dash was apart but still had the same problem.
Any ideas? Is there something wrong with the head unit that allows the cd player to eject disks but not do anything else of could it still be wiring somewhere?
Replies (7)
ttocs on 05/7/2007 11:57:44
I thought I worked on the worst cars out there but I never found any dead rodents.....
Turn power on to the deck and see if you can get it to recreate the problem through a series of technical taps. First just wiggle the hrns and see if it goes on and off. If it does look for loose connections at the hrns or for pins comming out. If that doesn't do anything then try tapping on the top of it first with your finger, then a light slap with your hand open, then with your hand shut, next with a baseball bat and finally a 15 lb sledge..... Ok you shouldnt' need a bat or sledge, your foot will do. See if you can recreate the problem and then isolate it.
94cruiser on 05/7/2007 12:04:56
Thanks for your suggestion but unfortunately I've tried it all (minus the bat and the sledge). I only tried it when the deck wasn't working but haven't tired it when it was. I have wiggled the hrns and the connectors, tapped lightly and then more aggressively with a closed fist. None of this seems to make a difference.
I can get in the truck, start it up and the deck works. I then turn the ignition off and restart the truck and the deck doesn't work. While driving, the deck goes off and it doesn't seem to be associated to any "bumps in the road".
Could something in the deck be overheating??
swez on 05/7/2007 13:31:29
Hum, this is a new one... you may have to dig deeper into the dash and check the speaker/power wires as they feed outward from the HU. If they too have been chewed up, additional repairs are doable.
When the HU shuts off, do you note the HU being a bit on the very warm side? (Just place your fingers on the face panel and feel for heat) I would expect it to be a little warm after a few minutes of playing at 50% of full volume or more. However, if it gets hot to the touch, that may mean a shorted speaker wire or 2.
Also, does this HU have a removable face panel? (Anti-theft) If yes, remove the face panel and clean the electrical tabs with an eraser. Look for bent or slightly mis-aligned tabs and the like.
Swez
PS The dead rodent probably got electricacuted if he bit the main power wire and was grounded to some metal while gnawing at the wires. Serves the little bugger right huh? GRIN
94cruiser on 05/7/2007 13:58:34
Thanks for the suggestions.
I don't think it is outgoing speaker/power wires since the display on the deck is dead (no display or lighted buttons but cd player ejects). I have considered the idea that the main stereo hrns wasn't the first set of wires it chewed, I just don't know where to start looking to resolve this type of problem.
I haven't noticed that the HU is hot but I will try to be more observant in the future. Also, the face plate is not removable.
If I were to get a service manual, do you think that would be helpful at all or should I just get a new HU?
Thanks again.
swez on 05/7/2007 14:40:46
There are 2-3 main power lines in the harness, and a ground.
1. Yellow is a constant 12 volt supply (Always powered)
2. Red wire is a switched 12 volt supply that is connected to ACC/IGN. This wire only has power when the key is in ACC or Rum modes.
3. Orange is often an ILLUMINATION wire feed (Controls HU lights and display levels via the dash lighting dimmer
4. Black is your ground and should be grounded to metal in the dash or floor pan.
If there is no display or lighted feature buttons, I'd look at the RED power line and ground first. (Probe these wires with a DC voltmeter) If you see no voltage when the key is in ACC/Run modes, trace it back or run a fresh wire here.
Do the same test on the YELLOW harness wire. It should have power off the battery at all times. Probe this line and ground the black meter cable. If you don't get a solid 12.0-12.5 volts DC here, replace this wire.
Finally, probe the ORANGE line, (if connected) to see if there is a voltage present when your parking lights are on. The voltage readings will vary, depending on the dash light dimmer settings. Most HU's can bypass this feature and we set the ILLumination levels off the HU manual settings functions outlined in the user's manual.
Comments?
Swez
cplkittle on 05/7/2007 14:46:38
The fact that it is spitting the CD out when it goes out tells me that it is either losing power on the yellow wire, or it is losing ground. The first thing that a CD player does when you plug it in is eject any CD that might be in it.
I would look here first. Ground the radio to a bare metal spot in the dash that tests well as a ground. Next, run a wire out to the battery and connect it to the yellow (constant) wire on the radio. Be sure to disconnect the yellow wire from the factory wires first.
See if that helps. If it does, we can narrow it down to these two wires in the factory harness.
It could be that the factory ground is not sufficient for this radio.
trunkisloud on 05/7/2007 20:42:30
maybe the rat dropped a duece in the vents of the deck and shorted the board ....little overboard?
I took apart the dash and found a dead mouse on top of the stereo (nice!) and chewed harness wires! I spliced in new wires and disassembled and cleaned the head unit but to my dismay, the stereo still only works intermitently. I checked the groud with test leads while the dash was apart but still had the same problem.
Any ideas? Is there something wrong with the head unit that allows the cd player to eject disks but not do anything else of could it still be wiring somewhere?
Replies (7)
ttocs on 05/7/2007 11:57:44
I thought I worked on the worst cars out there but I never found any dead rodents.....
Turn power on to the deck and see if you can get it to recreate the problem through a series of technical taps. First just wiggle the hrns and see if it goes on and off. If it does look for loose connections at the hrns or for pins comming out. If that doesn't do anything then try tapping on the top of it first with your finger, then a light slap with your hand open, then with your hand shut, next with a baseball bat and finally a 15 lb sledge..... Ok you shouldnt' need a bat or sledge, your foot will do. See if you can recreate the problem and then isolate it.
94cruiser on 05/7/2007 12:04:56
Thanks for your suggestion but unfortunately I've tried it all (minus the bat and the sledge). I only tried it when the deck wasn't working but haven't tired it when it was. I have wiggled the hrns and the connectors, tapped lightly and then more aggressively with a closed fist. None of this seems to make a difference.
I can get in the truck, start it up and the deck works. I then turn the ignition off and restart the truck and the deck doesn't work. While driving, the deck goes off and it doesn't seem to be associated to any "bumps in the road".
Could something in the deck be overheating??
swez on 05/7/2007 13:31:29
Hum, this is a new one... you may have to dig deeper into the dash and check the speaker/power wires as they feed outward from the HU. If they too have been chewed up, additional repairs are doable.
When the HU shuts off, do you note the HU being a bit on the very warm side? (Just place your fingers on the face panel and feel for heat) I would expect it to be a little warm after a few minutes of playing at 50% of full volume or more. However, if it gets hot to the touch, that may mean a shorted speaker wire or 2.
Also, does this HU have a removable face panel? (Anti-theft) If yes, remove the face panel and clean the electrical tabs with an eraser. Look for bent or slightly mis-aligned tabs and the like.
Swez
PS The dead rodent probably got electricacuted if he bit the main power wire and was grounded to some metal while gnawing at the wires. Serves the little bugger right huh? GRIN
94cruiser on 05/7/2007 13:58:34
Thanks for the suggestions.
I don't think it is outgoing speaker/power wires since the display on the deck is dead (no display or lighted buttons but cd player ejects). I have considered the idea that the main stereo hrns wasn't the first set of wires it chewed, I just don't know where to start looking to resolve this type of problem.
I haven't noticed that the HU is hot but I will try to be more observant in the future. Also, the face plate is not removable.
If I were to get a service manual, do you think that would be helpful at all or should I just get a new HU?
Thanks again.
swez on 05/7/2007 14:40:46
There are 2-3 main power lines in the harness, and a ground.
1. Yellow is a constant 12 volt supply (Always powered)
2. Red wire is a switched 12 volt supply that is connected to ACC/IGN. This wire only has power when the key is in ACC or Rum modes.
3. Orange is often an ILLUMINATION wire feed (Controls HU lights and display levels via the dash lighting dimmer
4. Black is your ground and should be grounded to metal in the dash or floor pan.
If there is no display or lighted feature buttons, I'd look at the RED power line and ground first. (Probe these wires with a DC voltmeter) If you see no voltage when the key is in ACC/Run modes, trace it back or run a fresh wire here.
Do the same test on the YELLOW harness wire. It should have power off the battery at all times. Probe this line and ground the black meter cable. If you don't get a solid 12.0-12.5 volts DC here, replace this wire.
Finally, probe the ORANGE line, (if connected) to see if there is a voltage present when your parking lights are on. The voltage readings will vary, depending on the dash light dimmer settings. Most HU's can bypass this feature and we set the ILLumination levels off the HU manual settings functions outlined in the user's manual.
Comments?
Swez
cplkittle on 05/7/2007 14:46:38
The fact that it is spitting the CD out when it goes out tells me that it is either losing power on the yellow wire, or it is losing ground. The first thing that a CD player does when you plug it in is eject any CD that might be in it.
I would look here first. Ground the radio to a bare metal spot in the dash that tests well as a ground. Next, run a wire out to the battery and connect it to the yellow (constant) wire on the radio. Be sure to disconnect the yellow wire from the factory wires first.
See if that helps. If it does, we can narrow it down to these two wires in the factory harness.
It could be that the factory ground is not sufficient for this radio.
trunkisloud on 05/7/2007 20:42:30
maybe the rat dropped a duece in the vents of the deck and shorted the board ....little overboard?
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