"the external system is not connected/check the connection of AC" (1 Viewer)

[TX100]

My 2006 lx470 recently lost all controls of nav, ac, outside temp, and audio. Whenever I press the nav/audio control buttons on the left I get "The external system is not connected". Whenever I press the AC controls along the bottom of the screen I get "Check the connection of the air conditioner". So far I have done the following:

-Unplug the battery for an extended time, reconnect
-Checked all the wiring connections on the back of the nav/head unit
-Replaced the old nav unit/screen with one that works
-Checked nav fuse under the hood

I have read everything I can find but to no avail. Unfortunately I'm going to have to head into the Lexus dealership if I can't get this fixed. It's 100 everyday where I live and I have little kids. No ac, not happening. Any help would be appreciated

 

[Spike555]

Have you read up on the broken solder joint on the circuit board?

 

[SLVRSCRN]

No knowledge of the AC issue, but I do recognize one cause of the 'external system not connected' message.

I completely tore down my center console to replace a broken DVD changer with a working unit; the 'external system' message persisted UNTIL I reconnected the second-row AUX jack/volume controls to its wiring clip.

Not sure what else you may have disconnected so YMMV, but in my experience the integrated infotainment/HVAC controls on these cruisers don't behave well if even one component is disconnected or if connections are loose. Good luck.

 

[TX100]

Have you read up on the broken solder joint on the circuit board?

I did briefly.

No knowledge of the AC issue, but I do recognize one cause of the 'external system not connected' message.

I completely tore down my center console to replace a broken DVD changer with a working unit; the 'external system' message persisted UNTIL I reconnected the second-row AUX jack/volume controls to its wiring clip.

Not sure what else you may have disconnected so YMMV, but in my experience the integrated infotainment/HVAC controls on these cruisers don't behave well if even one component is disconnected or if connections are loose. Good luck.

Thanks for the info. I just bought this truck a couple months back and have had a few problems already. The CD changer has never worked but everything else did. Now its everything. Might try going into the center console. About how long did it take you to access the wires?

 

[SLVRSCRN]

I did briefly.

Thanks for the info. I just bought this truck a couple months back and have had a few problems already. The CD changer has never worked but everything else did. Now its everything. Might try going into the center console. About how long did it take you to access the wires?

First time, less than two hours working very slowly with breaks. You can likely get the trim/covers removed in less than one hour. I will check this evening if still have my notes, if so I will share. Inside the console, there's two electrical parts: the CD/DVD changer (inside center console), and the AUX ports/volume controls (facing second row). If you haven't disconnected either of those yet, I would leave those alone for now. My Nav and HVAC controls DID function properly when I had disconnected/removed both DVD and AUX modules -- not sure my first post was clear.

The issue seems confined to Nav/HVAC as you described.

Did your system function properly at all since purchase? Do you have any other info on failure event? Perhaps some other mudders can share similar lessons.

Godspeed.

 

[November Sun]

I fought this problem with my 04 LS430, same warnings, intermittent stereo, mind of its own. I checked every fuse to no avail. Took it to Lexus and they just wanted to replace it with a remanufactured head unit for $1700. I found a post on Club Lexus and sent it to www.autobeyours.com.
Paid $299 and dude had it fixed and sent back in a week and all has been good. It's a cold solder joint that needs to be fixed.

Hope this helps.

 

[TX100]

I fought this problem with my 04 LS430, same warnings, intermittent stereo, mind of its own. I checked every fuse to no avail. Took it to Lexus and they just wanted to replace it with a remanufactured head unit for $1700. I found a post on Club Lexus and sent it to www.autobeyours.com.
Paid $299 and dude had it fixed and sent back in a week and all has been good. It's a cold solder joint that needs to be fixed.

Hope this helps.

Thanks guys. Definitely good info. Does anyone know what the exact part/part number has the bad solder joint?

 

[TX100]

First time, less than two hours working very slowly with breaks. You can likely get the trim/covers removed in less than one hour. I will check this evening if still have my notes, if so I will share. Inside the console, there's two electrical parts: the CD/DVD changer (inside center console), and the AUX ports/volume controls (facing second row). If you haven't disconnected either of those yet, I would leave those alone for now. My Nav and HVAC controls DID function properly when I had disconnected/removed both DVD and AUX modules -- not sure my first post was clear.

The issue seems confined to Nav/HVAC as you described.

Did your system function properly at all since purchase? Do you have any other info on failure event? Perhaps some other mudders can share similar lessons.

Godspeed.

Thanks slvrscrn. The guy I bought the rig from is solid and has an 06 lx470 that he totaled recently. He has already sent me the nav screen for free and now is offering any other part I need to fix the problem at no cost. Everything was fine when I purchased 5k miles ago. Quite impressed with how he has stepped up this far. He's on i8mud and really values his Rep here. I will let all know what the issue winds up being. Thanks again for the great info.

 

[jerryb]

There are more than one or two fuses involved here. Does nothing have power now but the screen? the radio doesn't?
If your ac worked before but now it doesn't, and now the radio doesn't have power but it did, then I would go back and figure out why there isn't power.

If the radio works now, is it communicating with the screen? Do the connections look good? tx- and tx+ wires look good? (pink and blue)
Do the AC amplifier connections look ok?

just for info, the nav ecu, television ecu, rear audio controls and dvd changer do not have to be connected for the ac to function normally.

I think it's very difficult to fix these kind of issues without the paper manuals. If your seller will send you stuff I would ask for the AC amplifier, and if he has manuals maybe you could barrow them?
I think if you already swapped screens (looks like you swapped the entire center section?) then the solder issue might not apply, possibly.

 

[TX100]

Found the problem. SMDH!!! It was the aftermarket bluetooth I had installed. It worked perfectly for months so it really wasn't suspect. Thanks for all the good info guys. Just shows how much these vehicles DO NOT like aftermarket tweeks.

 

[meatloaf]

TX100, good to hear you got it fixed... Was the problem in the wiring? I have been tracking issues with mine with not luck. Truck used to be my brother's and he said he had sent out MFD to Boardmedics and they supposedly told him it was good. But when I run diagnostics it tells me that the MFD is bad. Truck does have aftermarket XM stuff on it.

 

[ftzgrlds1]

TX100

I've been running an aftermarket bluetooth in my 2004 LX470 for probably a year with no problems until a couple of days ago; intermittent AC, "check external connection" prompts...etc.

Did you install a new bluetooth? If so what kind.

Did you juts re-plug in the CD player to determine the bluetooth was the culprit?

Thanks in advance...

Found the problem. SMDH!!! It was the aftermarket bluetooth I had installed. It worked perfectly for months so it really wasn't suspect. Thanks for all the good info guys. Just shows how much these vehicles DO NOT like aftermarket tweeks.

 

[dannyLX]

I recently have been getting the same issues. I too have an aftermarket aux converter that is connected in the CD input on the NAV screen. Worked perfectly fine before and I think it may be the issue. I have the same questions as the reply above, did it work after you installed a new bt unit? Did you just re-plug in the CD player to determine the bt was the culprit?

 

[LonghornMudder]

2006 LX470 just started showing same behavior described in original post above. Pressing nav/audio control buttons on the left yields "The external system is not connected", and pressing the AC controls along the bottom of the screen yields "Check the connection of the air conditioner". I also tried unplugging the battery overnight and checked fuses under the hood.

I've had a BT-45 bluetooth audio unit installed & functional in this vehicle for three years now, but the touchscreen error messages began after an inadvertent battery drain. I'm going to try disconnecting the aftermarket bluetooth unit, but wanted to echo the described behavior reported by others and check to see if anyone had identified anything in particular which might explain the change after a 36-month track record of "good behavior" by the upgraded audio configuration.

 

[excessive]

Did anyone ever resolve this issue ?

 

[TX100]

Did anyone ever resolve this issue ?

 

[TX100]

Did anyone ever resolve this issue ?

It turned out to be a short with my aftermarket bluetooth. I unplugged everything then plugged it back in and it returned to normal function.