5150evh

Hello everyone!

For the past 2 years my navigation screen has acted erratically. I only get the full function of it when the weather is either really cold or really hot outside. The screen will work for a minute or two and then go black. My A/C, radio, and CD player all work but I can't adjust anything since the buttons are not appearing on the navigation screen.

So I've learned to live without it for a while now. My Lexus dealer told me it would cost $2,000 to replace it.

Here's what bothers me: After discussing the problem with the service guy he deduced that there was a short somewhere, but due to company policy I would have to buy a new screen if I wanted it fixed. I got the impression from him that the fix for the screen wasn't a huge deal, but my only option was to buy a refurbished navigation screen. What steamed me more was that it is then required for Lexus to take possession of my old screen, which they would fix (provided it's an easy fix) and re-sell for $2,000.

So, I'd really like to fix this myself if possible. Like I said, the screen works...when it works, which leads me to believe maybe a fuse is out somewhere?

If anyone has any advice, I'd really appreciate it!

Slvr surfr

iTrader: (1)

Seems to me you have an connection issue since it seems temp related. Plastic and some metal parts and connections contract and expand when either cold or hot. If possible, check the connector/s on the back of the nav screen if you can get to it. Make sure all connections are fitted well and make sure there are no kinks in the wire harnesses that attach to it. Its a no-cost first step in trying to troubleshoot your problem.

5150evh

Silver,

Thank you very much for the prompt response.

What is the easiest way to remove the panel so I can get behind the nav screen. Are there any tutorials online? Are there any special tools I need?

Many thanks

Slvr surfr

iTrader: (1)

No problem!

Well you may want to do search thru the FAQs links of this forum and also do manual search. You can also ask any of the moderators for help with you questions and maybe some of the other members can chime in with a quick breakdown of the dash removal.

Always glad to help when i can.

DDLexus

FWIW,
I have a 2004 Toyota Sienna van with a factory NAV unit in it. When we go down to FL for vacation and leave it out all night the NAV is slow to turn on. Sometimes we will drive well over 30min before it finally comes on. This also happened while we left the car out of our garage during rainy weather for a week. I deduced that the problem was humidity related. I took apart the dash, pulled all the fuses and made sure everything was well seated. It seemed to resolve the problem. So, my advice... take out the unit, disconnected everything and then put it back together. Find all fuses related to the NAV, RADIO, AC, etc. and pull/replace. Consider replacing all the fuses with NEW ones with the same rating.

airtime

Here you go... Just read through the first part.
https://www.clublexus.com/forums/ls4...ide-w-pix.html

5150evh

Thank you very much for the informative response. I really appreciate it!

As I type this, the NAV unit has been completely taken out and is in pieces in my car. So I disconnected everything, re-connected everything, and the problem is still there.

Major noob question here : What part are you referring to as the fuses? Are those the plastic white connector blocks with all of the wires in them?

Where can I buy the appropriate replacement fuses? And is there a tutorial on how to replace them on this forum? Many Thanks!

5150evh

Airtime, thank you! This was a huge help!!!!

5150evh

So I took apart the entire console, disconnected everything, re-connected everything, and the problem is still there. As far as the kinks go, the wires are pretty bound together with electrical tape.

Any chance I have a blown fuse somewhere? Any other ideas?

brio_ls

Try searching the factory repair manual. For example here - Black Screen(no image appears on navigation....)
and here - Problem Symptoms Table

Slvr surfr

iTrader: (1)

While having the ignition on,try to gentley wiggle all the harnesses and even the screen itself to see if there is any intermittent behavior of your conditions.

5150evh

Thanks again for your help.

I gave this a shot and strangely enough there isn't even any intermittent behavior. I gently manipulated the wires hoping something would kick in. I even cleaned the plugs with canned air and a contact cleaner (De Oxit) and still nothing.

StanVanDam

If the problem only occurs during extreme temperature changes, I think the wires on the back of the nav unit are likely much too big to be affected.

The problem is more likely to be one of these:
* bad ribbon cable connection between the LCD screen and the circuit board behind it
* microfractures of PCB (printed circuit board) lines (unfixable)
* microfractures of solder joints connecting circuit board components (ie. resistors/transistors/capacitors/ICs) inside one or more of the following: the centre console nav screen, the trunk nav ECU, or the trunk stereo amplifier. This has a slight chance of being fixable.

I would reseat the plugs on the trunk nav ECU and on the amplifier as an easy check. I would then take apart the nav screen to get at the circuit board, and resolder and reseat all connections.

In the past, was the car exposed to a lot of temperature extremes?

5150evh

Stan,

Thanks for your valuable feedback.

"I would reseat the plugs on the trunk nav ECU and on the amplifier as an easy check. I would then take apart the nav screen to get at the circuit board, and resolder and reseat all connections."

Where exactly is the trunk NAV ECU? And what do you mean by "reseating the plugs?" Do you mean resoldering them?

I would imagine that the car was exposed to some extreme weather temperatures as the car used to be my father's in Kansas. Kansas is known for extreme erratic weather. The summers can get to 105 and the winters can get to 10 degrees. While half the time the car was kept in a garage at home, when he went to work I'm sure the car was outside.

Thanks again for the help.

5150evh

I went and purchased a circuit tester and the 2 white multi pin plastic plugs that connect to the back of the Nav screen are powered (i.e. the test light turned green for exactly half of them, I'm assuming the other half are grounds).

Then I decided to take apart the entire nav screen. I pulled out every single ribbon connector, cleaned it with contact cleaner, and re-connected it. I've used a soldering knife with wiring before but never on a PCB board. So I had no idea what to look for, but to my untrained eye everything looked solid (i.e. no obvious disconnections.) So I didn't re-solder anything.

So I carefully put the entire thing back together, turned on the car and... nothing. I still get the "The external device is not connected," message.

Thoughts? (All of you guys who have chimed in, I really appreciate your help. I really appreciate it.)