Need Help Diagnosing Problem

[knmaynard]

It's gettin cold, so this is pretty important.

Lights on swithes turn on, seats never heat up.

How hard is it to diagnose, and how hard to fix, if elements (or whatever makes it hot) need replacing?

Is my best bet going to the dealer? (Somebody say no.)

Seats are in great shape, so not doing any reupholstering to coincide with working on heating.

[jbarhorst2]

Is it both seats??

[knmaynard]

Is it both seats??

←

Yes, it is. Does that mean anything?

[jbarhorst2]

Yes, that is probably a good thing.

I have the factory service manuals for the '97 SC300/400 and there is a section devoted to this.

Since it is both seats, it is my opinion that it is probably not the heaters themselves inside the seats. It is probably something common to both.

The service manual lists the following items to check.

1. ST HTR fuse on relay block 4

2. IG Main Relay on relay block 4

3. Seat Heater switch

4. Wire Harness

5. Seat Heater

This is the order you should check them.

Start with the fuse, and let me know if it is good.

Tom

[knmaynard]

Yes, that is probably a good thing.

I have the factory service manuals for the '97 SC300/400 and there is a section devoted to this.

Since it is both seats, it is my opinion that it is probably not the heaters themselves inside the seats.  It is probably something common to both.

The service manual lists the following items to check.

1. ST HTR fuse on relay block 4

2. IG Main Relay on relay block 4

3. Seat Heater switch

4. Wire Harness

5. Seat Heater

This is the order you should check them.

Start with the fuse, and let me know if it is good.

Tom

←

Awesome, thanks. Will check it here in a bit, and let you know what I find.

This board has already saved me a lot of money, and looks like will be saving me even more.

[SKperformance]

I would get a volt meter and monitor it while driving as most lexus heaters are working but are underpowered by the alternator

mine was until i changed the battery cables and now i can actually feel them work great