Lexus Repair: 94 LS 400 Electrical Nightmare, fuse panels, blown fuses


Question
Hi Mr. St. Amand!

Regarding my '94 LS 400....I hit the brakes, roll down the window (or do anything requiring power) something else cuts off (usually the radio). This happens in cold or warm weather. I've also lost the inside tail lights, which may have shorted out when I replaced the power antenna.  In cold weather (like now!), the panel lights won't come on until the car warms up significantly.  Is any of this related?  

Thanks,
Priscilla

Answer
Hi Priscilla,

What an interesting question you've posed.

It sounds like you have 3 different things acting up, but I don't think they are necessarily related to each other.

First, when the battery charge is low (which can especially happen in cold weather) the first thing that the car will turn off (in order to conserve power) is the radio.  So, after making sure that your battery is the right size and specification and is up to the task, check for loose or corroded battery connections, which would prevent the vehicle's electrical system from getting all the "juice" it needs from the battery.

Second, any circuit (such as the taillights you mentioned) that may have been "shorted out" is safety-protected with a fuse.  Check the fuse panels both inside the car, near the driver's and passenger's foot wells, and also under the hood for a blown fuse.  If you locate and replace the fuse and it blows again, you have a short to ground in that circuit which must be diagnosed and repaired ASAP.

If there are no blown fuses, and the bulbs are ok, then you have lost a power connection or a ground connection to the lights.  This too, will have to be diagnosed by a qualified technician.

Third, The combination meter lights (and needles) are like fluorescent tube lights that you'd put in a home ceiling fixture (only really tiny).  Unfortunately, they don't like cold weather.  To compensate for this, there are little ceramic heaters near them to keep them warm on cold days (no, I'm not making this up.)  It seems those little heaters are not working on your vehicle.  These heaters are not serviceable, requiring the replacement of the combination meter.

On the up side, some Lexus dealers have access to independent electrical repair shops which rebuild the circuit board and heaters, saving you quite a bit of money over buying a new combination meter.

Hope that helps.

Leonard