Ls400 Radio And A/c Fan Gone Haywire...

[TSO]

Hello! My first post :) 1997 LS400 Coach edition here.

yesterday on my hour long commute, the radio started getting SLIGHTLY intermittant. As I drove, it slowly got worse. I then noticed that the fan on the ac was also cutting out in precise timiing with radio. Over the course of the hour, it slowly got worse until I pulled up in my driveway. There, I left the car running and tried to diagnose it, and it they stopped alltogether.

The funny thinng is, they're not COMPLETELY dead. All lights come on normally on both, and if you turn the radio up full blast, you can barely hear the station. This is true on radio OR CD. Same with the air - it comes on, compressor kicks in, engine idles up, and the fan just barely blows (cold air), no matter what the fan setting is.

Two things I can think of -

1. Had a PS leak through the last year, very minor, but found the leak and sealed it (vacuum hose plug) and cleaned everything up as best I could. It worked, and no problems since, and alternator seemed to work fine.

2, Had the antenna mast break last weekend, and replaced it the day before the problems came. The antenna seemed to work fine, and I drove it a day without problems.

So, with these two repairs/incidents documented, from readin here I guessed it COULD be -

- the trunk hinge wire harness. I had to jockey around the trunk lining and that whole area quite a bit to get the antenna unit in and out several times to get that repair done. COuld very easily have put strain on the wiring harness. However, in reading through the forum, I couldn't find any trunk wiring threads that specifically mentioned these two issues - radio and AC fan acting in tandem and then failing (or becoming tremendously decreased).

OR,

- Alternator failure. The alternator worked fine for months after the PS punp repair. Also, everything else on the car seems to be fine. I haven't driven it much since yesterday, only around the neighborhood, but I get no idiot lights on the dash, and all other functions including starting, running, etc. seem to be fine. Could be running on battery, I guess, but the battery is old and in pretty marginal shape anyway, and so I think would have died by now.

Any thoughts, and THANKS FOR YOUR HELP!

[TSO]

Anyone?? I would love to be forarmed before taking it in to the dealer.

By the way - where is the 1997 LS400 forum? I see that this only goes to 1996, and the other forum is for 430's and 460's only.

Thanks :)

[TSO]

Ok, here's an update (since no else seems is going to reply ),

I've ruled out alternator - car has been driving fine for three days now.

I've just about ruled out trunk hinge wire bundle fault - when the radio and fan are working, I can't get them to sputter by shaking or moving the wire bundle, and when they are NOT working, I can't get them to start intermittantly by doi ng the same. Ergo, propbably not a fault in the wire bundle, at least at that spot.

More info and narrowing - I believe that it's the radio AMP and the fan mototr that are cuting out, 100% or 0%. The faint sound I hear through the speakers is simply the pre-amp signal going through the non-powered amp and to the speakers. The slight air from the vents when the fan is dead is from the fresh air fan, which is independant of the AC fan blower.

More diagnostic info - the two items always work properly after the car has been sitting and cooled off. In fact, it was a cool night last night and they worked for the entire hour commute home. Out again today though, after 30 minutes of driving. Also, when it's getting to the point of going out, bumps in the road or hard braking cause it to go out momentarliy

This would seem to indicate a fuse or relay somewhere with a bad connection or almost-broken connection - heat warps the contact until it goes OUT of contact. Or, same scenario with a wire, I suppsoe, though I've never heard of a wire doing this on-off thing related to heat.

Any thoughts? IS there somewhere I can download a schematic so as to trace the power path from alternator to fan/amp?

Thanks for any input. I know I'm "new", and folks tend to ignore the new or hold in disdain the "ignorant new guy", but I'm getting desperate. Houston get's REALLY hot in the summer...:)

[TSO]

Problem fixed!!!

Hooray!

[Robin C]

Hi TSO:

Read this thread: http://us.lexusownersclub.com/forums/index...showtopic=57291.

He had the same problem and traced it down to the car-phone ECU in the trunk! Apparently, a leak in the trunk intermittently shorted out the ECU and made it think that the phone had been lifted. Apparently, the "mute" feature on the phone cuts in. This mutes the radio and slows down the blower. Go figure!

Anyhoo, read the thread.

BTW, how did you fix your problem? You say that it was fixed, but please give details.

Cheers,

Robin

[90LS400Lexus]

- the trunk hinge wire harness. I had to jockey around the trunk lining and that whole area quite a bit to get the antenna unit in and out several times to get that repair done. COuld very easily have put strain on the wiring harness.

Oh my. I didnt know this trunk hinge wiring loom issue lingered into the 1997 models. WOW!