How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Toyota Service Your Own Question
Toyota Service
Toyota Service, Lexus and Toyota expert
Category: Lexus
Satisfied Customers: 4945
Experience:  30 + years of experience; Multiple Award Winning Svc Mgr; Just Answer Customer's Choice Award Winner
Type Your Lexus Question Here...
Toyota Service is online now
A new question is answered every 9 seconds

I have a 1994 LS400 that I am trying to make road worthy

Customer Question

Hi, I have a 1994 LS400 that I am trying to make road worthy before I give it to my son to drive. Currently I am looking to solve an issue where when the head lights are turned on the stereo lights turn off. I am also assuming that the cluster lights turn off but since this "flickers" at the moment it is hard to tell if turning on the head lights also causes the cluster to go out. (I am having a cluster guy repair this but want to solve the first problem in case this also fixtures the cluster problem too). Interior light dimmer seems inoperable.
JA: Have you checked the vehicle's manual for this?
Customer: Check the manual for what?
JA: What is the model of your '94 Lexus?
Customer: LS400
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: I have not tried anything yet. We just got this vehicle and have fixed other issues first. Now onto this issue.
JA: Anything else you want the mechanic to know before I connect you?
Customer: No just this issue for now, thank you.
Submitted: 1 year ago.
Category: Lexus
Expert:  Toyota Service replied 1 year ago.

Hello. Welcome to Just Answer. Please allow me to assist you. Please advise if the instrument panel lights go out when the headlamps are switched on. Thanks

Customer: replied 1 year ago.
Instrument panel flickers and works intermittently now (separate issue) I believe I am getting cluster repaired as separate issue so I can not be sure. The one time that it was working at night as soon as I turned on head lights it did got out so I assume that yes it goes out but can't say 100%
Expert:  Toyota Service replied 1 year ago.

Thank you for the fast reply. I do not think you have a cluster issue. I believe that you have a faulty instrument panel light level control. If the rheostat is worn (common on a 20 year old car), the dash lights will flicker, and most often, they will just go out. This also shuts down the heater controls as well as the radio illumination (but not the radio operation; that is a separate circuit). I would have the dash dimmer control looked at before I spent money chasing a cluster issue that is not the problem...Cluster failures are exceptionally rare on these vehicles. If you have any questions, please feel free to reply. Thanks

Customer: replied 1 year ago.
The radio is illuminated when head lights are not turned on. This issue only happens after turning on the head lights then the radio lights turn off. There is also no issue with any heater conforms whether head lights are on or off. As I stated in beginning the dimmer switched seemed to be not operating. You haven't really added any insight. I had actually asked to cancel request immediately after seeing this was $5 but was actually $27. I also Emil in for cancellation as well as called. I hope that I am not going to be charged $27 for something I already knew and told you.
Expert:  Toyota Service replied 1 year ago.

You may not be aware of this, but, the action of the headlamps being turned on activates a separate circuit on this vehicle. We have observed this condition before in the shop. I stand by my recommendation.

Customer: replied 1 year ago.
Ok was Exactly is your recommendation?
Customer: replied 1 year ago.
Just telling be that the dimmer control is faulty (which I actually said in my original email) isn't your recommendation. It was mine. I would expect for $27 that you could give me better instruction on replacing and OEM part numbers.
Expert:  Toyota Service replied 1 year ago.

I understand your frustration. But I cannot understand why you are so upset; I ma trying to assist you, and trying to help you avoid paying good money to someone to "look" at the cluster when the cluster is most likely not the issue. If I were you, I would have someone who is qualified to measure the resistance value of the dashboard rheostat to ground. If it is faulty, the readings will indicate this rather quickly. The readings should move slowly as the control is moved. If the reading drops out, or has no reading at all, then , the unit IS faulty and needs to be replaced. .

Customer: replied 1 year ago.
I'm more upset that instead of $5.00 I get duped into $27 and even though I asked to cancel within 1 minute of realizing that I was in for more than I bargained that this request didn't get cancelled. I do appreciate that u donation but when I called Lexus they had never heard of this issue however within my research see that cluster issues are actually quite common in the early Lexus vehicles.Do you have this rheostat part number?
Expert:  Toyota Service replied 1 year ago.

Interesting. I have been associated with these vehicles since 1990 and I have to disagree with that statement.

Expert:  Toyota Service replied 1 year ago.


Customer: replied 1 year ago.
Expert:  Toyota Service replied 1 year ago.

Look above you response that is in CAPS

Expert:  Toyota Service replied 1 year ago.

I will pass your refund request on to the site administrators. Thanks for choosing Just Answer.

Customer: replied 1 year ago.
Thank you