94 ls400. I am having intermittent power issues. My blower fan, brake lights, and instrument panel dimmers all cut out intermittently. I also lose cruise functionality, but i still have the cruise icon on the panel. I am also having to use the park lock override button in order to get out of park. I have checked all fuses and breakers, both physically and with a test light. It looks like i am getting intermittent power to the green 40a rr defog breaker as well. Cant find anything else out of place. CEL, TRAC light, TRACOFF light, and abs light are all on. Are there any relays that would have all of these systems in common? Is there a point where a single power source connects all these systems? Tried replacing stoplight switch already. No change. I pulled the codes but didnt get anything helpful. Any suggestions appreciated.

 

The left side of the trunk lid is a wiring harness. Check that for any broken wires and repair as necessary.

This one as well:
http://www.lexls.com/tutorials/lighting/bulbout.html

 

Thats been dealt with

 

Other thought is some rodent has made a meal of the wire insulator at some exposed point in the engine bay.

Have the ECU capacitors been dealt with?

 

Ecu capacitors haven't been dealt with to my knowledge. I did read up on those symptoms the other day and only a couple seemed to fit, but not all that well. However i have been over the entire engine bay and havent found any exposed, cracked, or frayed wires. Ive also checked my body grounds. Ive been taking voltage readings through my cigarette lighter throughout this process and there is no change in voltage there while things are acting up, so it seems that a large upstream draw is less likely?
Also, all of the electric motors for my heat settings still function, and my heater core is producing heat.
Also forgot to mention that i have no power under the dash at the following fuses: STOP 25A, FOG 15A, ECU-B 15A, MIR-HTR 10A, PANEL 7.5A, AND TAIL 15A

 

Ecu has been dealt with. Was able to call the company who did the work and confirm too. The technician also said that, in his opinion, the problems im facing are unrelated to the ecu.

 

I've had test lights light up with minimal voltage that sent me on wild goose chases. Granted, they were newer German cars and different systems. Do you have a way to check actual voltage through the fuses?

Does it happen during different driving conditions or is it 100% intermittent? No matter day or night, rain or dry?

"Also forgot to mention that i have no power under the dash at the following fuses: STOP 25A, FOG 15A, ECU-B 15A, MIR-HTR 10A, PANEL 7.5A, AND TAIL 15A"
What have you tried to do to rectify this issue? Have you swapped in new fuses? Have you looked at the wires leading into the block to see if they're burnt?
It's possible you have a short, it's also possible you had a surge of voltage and popped fuses. What is your voltage gauge saying while the car is running?

Do your brake lights actually work?

 

I'd simply check the terminal 1B of the FL box lifting it because all those loads STOP 25A, FOG 15A, ECU-B 15A, MIR-HTR 10A, PANEL 7.5A, AND TAIL 15A are getting the power from it using a thick white cable.

It would be the best if I were able to show you the FL box and the terminals for your quick action but sorry that I don't have any photos nor drawings of a 94.

 

This post might help you some although it's about a SC400. Especially the 2nd photo shows the terminals.
https://www.clublexus.com/forums/sc-...ml#post9169897

If the terminal 1B of the FL box is OK, the next step would be to check the other side of the white cable which is connected to the junction box under the dash ( behind fuse panel where those fuses STOP 25A, FOG 15A, ECU-B 15A, MIR-HTR 10A, PANEL 7.5A, AND TAIL 15A are there ).

 

I did try swapping fuses with no results. All wires and connections under the dash are tight and in good condition. Voltage reading is 14.2v. I have a voltage meter that ill probably begin checking my circuits with as a next step. Ive been having a hard time replicating or changing the condition with any consistency (part of why i havent been sure where to look). These issues just started at random when i stopped at a stop sign last week. At first it seemed like it could be manipulated by slapping the brake pedal with my foot, but now that seems more due to coincidence or change in inertia.

 

Thank you Yamae. That sounds promising.

 

Yamae for the win! It ended up being one of the wires on the fusible links being loose. Thanks everyone for the help! This forum saves my butt more often than i can count lol

 

Awesome news!

We need an 'Ask Yamae' thread in here..

 

Congratulations on your fix, 76 Mercedes.
I'm glad that you quickly fixed the problem and the quick report of the result.