98 Ls400 Blower Intermittent

lihtemup · December 1, 2012

Recently I have been having a problem where my fan does not blow intermittently. It seems the only thing that changes it is turning the car off and on. Although I have never litterally sit there turning my car off and on, some days it works and some days it doesn't. I have tried turning the ac or heat off and on repeatedly and turning the fan speed up and down and that does NOT kick the blower on. But then I will go inside somewhere come back out,, start my car and it works....any advice o how to diagnose, common issues, etc would be appreaciated!!!

lihtemup · December 1, 2012

Oh, do not think it is related because this started years ago but....my speakers on the passenger side work intermittently too, although this sometimes fixes itself with bumps in the road.

billydpowell · December 2, 2012

sounds like you have a ground wire problem.... and they are hard to find. you might install some universal grounds yo help....

landar · December 2, 2012

It could be an intermittent power connection somewhere, however, if it were say, a ground or fuse connection, I would think that the entire panel might blank out and come back on. You do not mention this so it leads me to believe that the issue is in the HVAC control itself. Perhaps a connector to the control module. With that said, you might check the voltage at the blower fan fuse to make sure it is always present.

steve2006 · December 2, 2012

There is a Blower Motor Relay Control Module attached to the fan motor casing, not the easiest thing to get to but a good place to check for the correct supplies, if is is switching on or loose wiring/plug.

lihtemup · December 15, 2012

Thanks everyone for the advice!! I will respond once I find the problem!!

1990LS400 · December 15, 2012

The intermittent right channel audio outage in my similar 2000 LS400 with Nakamichi was caused by loose balance control connection - resoldering it fixed it.

An HVAC blower speed issue like the one described can be caused by a phone circuit problem -- has this car ever had a dealer installed Lexus phone? When a phone call was in progress, the blower speed was reduced to its lowest speed. Consider checking the phone system wiring harnesses on the right side of your trunk or corrosion or dampness. If your car has never had a phone, the phone harnesses will be attached to a plastic bracket attached to the bottom of the recepticle. into which the tool kit slides.

lihtemup · December 16, 2012

Well, I discovered today (after taking my control panel out and checking for loose connections) that slamming the glove box makes the blower go off and on. My battery was dead on my ohmeter but once i get it going going to look harder at the blower control (the box the blower connects to). Need to look harder at the connections to the control module as well, but my son woke from his nap...so I put it all back together.

While I had the control panel out, I must have put a little more stress on my speaker problem, passenger front is worse now, more staticy and a little motor noise. Is the balance contol conection easy to get to? In the back of the stereo control I assume?

Thanks again Gentlemen!!

1990LS400 · December 16, 2012

Is the balance contol conection easy to get to? In the back of the stereo control I assume?

This company in Florida resoldered my balance control: http://carstereohelp.com/strlexus.htm I remember they were surprised it was the balance control and not something else. You could check ebay for a replacement radio and/or amp ... getting pretty cheap as these cars age.

billydpowell · December 18, 2012

That glove box thing made me think... on my old 96, after driving a while, my blower speed would slow down to nearly nothing. and stopping and coming back after a while it would work for a while before doing the same thing, turned out it was my cabin air filter was clogged.... may not be your problem, but it would not hurt to check it.