1990 LS 400

Always go directly to the ground and check it is clean and well connected. I speak mainly here of the body grounds. Battery to starter is fine cause it cranks well and headlights are operable, it's just the battery ground to the body that's giving you trouble. When electrical problems arise, Always go directly to the grounds first.

Power is supplied to the Power windows and sunroof through the power window circuit breaker. That circuit breaker is supplied power through the RAP (retained accessory power) Relay, the RAP relay also supplies power to the radio. The RAP relay is also fuse protected by the RAP fuse in the under hood fuse block. The RAP relay is energized by the BCM body control module.

The RAP relay is responsible for the radio and windows working after the igntion is turned off.

The first place to check would be the RAP fuse in the under hood fuse block and then the RAP relay in the Body fuse block.

A list of the BODY relay block located on the left side of the dash to the right of the interior fuse block is below:

(1) Park Lamp Relay (2) Courtesy Lamp Relay (3) Retained Accessory Power (RAP) Relay (4) Power Seats Circuit Breaker (5) Power Windows Circuit Breaker (6) Inadvertent Power Relay (7) Door Lock Relay (8) Headlamp Ground Relay (9) Driver Door Unlock Relay (10) Door Unlock Relay(1) Park Lamp Relay
(2) Courtesy Lamp Relay
(3) Retained Accessory Power (RAP) Relay
(4) Power Seats Circuit Breaker
(5) Power Windows Circuit Breaker
(6) Inadvertent Power Relay
(7) Door Lock Relay
(8) Headlamp Ground Relay
(9) Driver Door Unlock Relay
(10) Door Unlock Relay
(1) Park Lamp Relay (2) Courtesy Lamp Relay (3) Retained Accessory Power (RAP) Relay (4) Power Seats Circuit Breaker (5) Power Windows Circuit Breaker (6) Inadvertent Power Relay (7) Door Lock Relay (8) Headlamp Ground Relay (9) Driver Door Unlock Relay (10) Door Unlock Relay (1) Park Lamp Relay (2) Courtesy Lamp Relay (3) Retained Accessory Power (RAP) Relay (4) Power Seats Circuit Breaker (5) Power Windows Circuit Breaker (6) Inadvertent Power Relay (7) Door Lock Relay (8) Headlamp Ground Relay (9) Driver Door Unlock Relay (10) Door Unlock Relay

I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

I would inspect your wires at the starter. If you live up north then corrosion is bad, clean all wires going to starter. then clean wires to back of alternator. I seriously doubt that alternator is the problem, but if you remove it you can have it tested for free at most parts stores.

my radio is not working today changed my battery and i don't know my code

REPLACE BUSTED FUSES

check fues under hood

that is the interior lights and alarm,remote module

check your fuses would be 1st thing to do

Can some one tell me why dash lights flicke and dnt stay on i have a 93 ls 400

Hatterasnc,

You're alternator has gone bad and the vehicle was running on battery power. The "clicking" sound is your now dead battery that does not have enough power to turn over the starter. You might also want to check your power steering pump for leak. This is a know problem with early LS400s and will most likey be the cause of the alternator failure. I just dropped $1050.00 to fix the very same promblems you have.