No power to engine of my 1993 lexus ls400 after replacing alternator alternator fuse and engine main relay but interior lights and horn are working but nothing else

You have two options: 1) remove the negative cable for about 5 minutes. 2) you can remove your main relay/fuse. Good Luck

In the fuse box under the hood or in a box behind glove box.

Most relays are under the hood in the fuse box or a separate relay box. Diagrams should be on the underside of the covers

i would check the ground out inside the steering wheel before anything else. these can get bent or broken off during a good panic honk or during a fit of roadrage. once ok'ed i would have a helper with a test light or volt meter check the system as you honk the horn to find out where the voltage stops. where the voltages stops will be the problem

your radio system is amplified sound system, the amp. is in the rear compartment under the rear window area, need to get the radio car system checked by a professional, they are a little bit complicated. as far as the heater same advice. the alternator and battery ,mainly keep the car going, battery for starting, alternator just keeps the electrical systems on your car supplied with power.

Check the main Fuse panel in the interior and check the main Power Distribution box in the engine compartment. If all fuses and relays are good start checking for a grounded positive wire off the battery and have the alternator tested. Check the firewall for a ceramic relay that has two wires going to it. If you have one there try running a bypass across those two points and see if that gets you power. Don't crank the motor with it bypassed but you should detect power at the lights and instrument panel if you jump across the wires.

1993 Lexus LS400 wont idle but will run

Hi,

I suggest you check the main relays - any auto electrician should be able to find a faulty relay.

Safe motoring.