Lose power to rear left door

1998 LEXUS GS 400

128,000 MILES • 4.0L • V8 • 2WD • AUTOMATIC

ROB 1503

MEMBER
63 POSTS
FOLLOW

Hi,

I'm having problems with losing power to the rear passenger door. There are times when the window and power locks work and other times when it doesn't. I pulled both rear door panels of and swapped the black box that powers the door electrical components and the rear right keeps on working fine but the rear left does the same, sometimes it works and sometimes it doesn't. What should i do next? Any advice is appreciated and also is there a way someone can provide me with the door electrical wiring please if possible?

Thank you,
Rob

Mar 20, 2020 at 9:50 PM

JACOBANDNICKOLAS

CERTIFIED EXPERT
110,175 POSTS

Hi,

The first thing I would suggest checking is the ground. It may be weak, corroded, or damaged. It is a separate ground than the other side. I attached a picture from the wiring schematic and circled the ground wire. It is located on the left C pillar.

Note that it is a white wire with a black tracer and comes from the left rear door ECU. You could simply try making a new ground to see if that fixes the issue or check for resistance in the ground wire.

Check that and let me know what you find.

Joe

Image (Click to enlarge)

Mar 20, 2020 at 10:34 PM

ROB 1503

MEMBER
63 POSTS

Thank you. I'll make a new ground wire early in the morning and see if that solves the problem, if not I'll check resistance next as soon as i learn how to do that, lol. Would you mind telling me how to do that?

Thank you

Mar 21, 2020 at 11:31 PM

JACOBANDNICKOLAS

CERTIFIED EXPERT
110,175 POSTS

Hi,

If you check for continuity between both ends of the ground wire, it should show either 0 ohms or very close to 0. Set your multi meter to ohms to perform this. If there is no connection between the two ends, your meter won't respond. If there is excessive resistance, you will see high numbers.

Let me know if that helps.

Joe

Mar 22, 2020 at 6:16 PM