Navigation Screen Blank

[duhmel]

A number of threads here on the navigation screen going blank but I haven't been able to discover anybody with the cause and solution. In my case I was jumping the battery of my 2005 LS430 and momentarily crossed the cables and got a spark. Car was then jump started and everything works except for the Navigation screen and associated items - radio, CD, air conditioning. I checked the navigation system fuse and it was OK. Anybody solved this problem????

[landar]

First off, you are very fortunate that you did not do more damage. Seems to me someone else on the forum did this cable reversal some time back. Don't remember the outcome.

Did you check all of the fuses, radio, CD, A/C, etc? Use an ohmmeter to check. I have seen fuses that looked good to the naked eye but were actually open.

By crossing the jumper cables you basically put both batteries in series (which will cause a large current flow in the jumpers, being limited only by the internal resistance of the batteries and cable) but worse than that, the car that is jumping your Lexus is now putting a reverse voltage on your entire system. Depending upon the internal protection of the circuitry, you may have damaged a circuit card or unit that will need to be replaced. But do more fuse checking first.

Do you have any voltage on either side of the Nav. System fuse?

[Lejas]

I have the same question. I have checked all fuses, twice, replaced all fuseable link fuses (one was bad - the 140 amp), disconnected the battery cables, and my navigation, audio and hvac have no power. I also have a check engine and VSC light, and ABS light displayed. Changing the 140A fuse did allow me to shift it out of park and brought the dash back online. I keep searching all the forums, and have found several other similar cases, but no one has posted a solution for bringing the HVAC, audio, and nav back online.

[Lejas]

SOLVED - I checked all the fuses twice, had my son go over them all with a fuse meter, and finally, had my wife check the most likely blown fuses. She is much smaller than me, and discovered on the passenger kick panel, there is a row of fuses on the top that is covered by the carpet. So, when I was mapping which fuses to pull, the diagram was one row off. There is a fuse number 33 listed in the owners manual that is at the very top, concealed under the carpet. This was the fuse that controlled the AC / Nav and audio. So the solution is to find a very small person, maybe from a yoga class or the circus, and have them crawl up in that tight spot to pull the carpet back.

Another note: There are two fuse boxes under the hood. I had a fuel injection fuse blown in the second fuse box, too. Everything works perfectly now!