Footwell lights constantly on, need help

[johnsvx]

Hey guys, first post here and needing advice. I've had my 1997 for about 7 months now and it's been great. Nothing I couldn't figure out except for this:

The lights in the driver and passenger footwells are constantly on. No matter if it's 10 seconds or 10 hours after the doors have been closed, the lights still remain on. Has anyone had this problem before? Any solutions? I've tried looking at the wiring diagrams and I found something called step lights, but I believe those are the ones in the door. Other than that I'm not sure what to be looking for. Any help is appreciated!

John

[irox]

I think you've found the right one, the Step Lights are the lights in the foot well under the dash.

From the FSM I have, the "RH Step Light" is connector i19, LH is B77, these connect to each other, and to the Time Control Unit Assembly. This is under the right hand side of the dashboard, behind the glove box

Ref: 31 Wiring Diagram and Trouble shooting. page 73 for the Step Lights

I’ve gotten a little familiar with that interior wiring for a few weekends after diagnosing a faulty Time Control Unit:
http://www.subaru-svx.net/forum/showthread.php?t=64528
Not saying you've necessarily got a faulty Time Control Unit, but some of the diagnostic steps I tried might help.

First I would figure out why both of the Step Lights are not on, since there are on the same circuit. Blown bulb? Short some where? What voltage is each bulb getting? How is the ground of each bulb? How much resistance between the bulb grounds? Voltage between the grounds? etc.

First fix the problem with both the step lights coming on, then if they are still staying on when the car is off with doors closed, start working your way through the rest of the harness.

Good luck!
Ian
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[johnsvx]

The Time Control Unit Assembly is the only thing I can figure, because the lights are not turning off. Both lights work and it's definitely not a door open/closed switch because the other ones turn off. Besides the Time Control Unit, I don't believe anything would keep them on when all other conditions to be off are met.
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[irox]

A melted wire, melted connector, or some other damage to part of the harness could lead to this (I replaced a few partial melted connectors on my previous SVX). But, yeah, given my past experience with the Time Control Unit, I would look at diagnosing/testing the Time Control Unit.

Also, I re-read your original post, I'd mis-read that only one of the lights was on - sorry about that.

There is another thread about replacement/repair of the Time Control Unit. It seems there is MOSFET in the Unit that isn't fused and can blow/fail:
http://www.subaru-svx.net/forum/showthread.php?t=64455

I think I might have some PU7456s some where. I ordered some from China (but had to wait 3 months for them to be made) but got a working used Time Control Unit before they arrived.

Cheers,
Ian
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[Blacky]

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I just wanted to say that it may be confusing to new members to call the Time Control Unit a TCU. This acronym is usually used for the Transmission Control Unit, which works with the ECU to control the major operations of the engine and transmission.
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[svxcess]

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Originally Posted by Blacky

I just wanted to say that it may be confusing to new members to call the Timer Control Unit a TCU. This acronym is usually used for the Transmission Control Unit, which works with the ECU to control the major operations of the engine and transmission.

Very good observation, Blacky. I have edited the previous posts to replace that acronym with “Time Control Unit Assembly” to make it easier to understand.
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[svxcess]

Look at this thread. May be some helpful information or clues.

http://www.subaru-svx.net/forum/showthread.php?t=37930


There are 2 different part numbers for the Time Control Unit Assembly, dependent on year.

88001PA000 Time Control Unit Assembly, No. 1 (1992-1995)
88001PA030 Time Control Unit Assembly, No. 2 (1997-1997)

Both numbers are discontinued and no longer available from Subaru.
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[johnsvx]

Well, before I go and find all the wires in the car, what step should I take first? Is it easy enough to pull the time control unit and visually inspect it? Would I be able to tell if something is blown/broken? I'm handy with wiring but not too familiar with MOSFETs

[svxcess]

The Time Control Unit is directly behind the glovebox. There are a lot of screws that need to be removed so be patient.

here are images of the schematic for the unit. If you have the FSM, it is located in Wiring Diagrams Sections 6-2 and Body Electrical System 6-3.

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[johnsvx]

Thanks, I do have partial manuals but nothing totally complete. More to add to the collection haha. Looks like this is going to be my next project

[svxcess]

Here are the pdf manuals you need in their entirety. Download from my Google Drive.


Body Electrical System 6-2. See page 48

https://drive..com/file/d/0BxZVixvKOy5sWkxreEk3bE03NTg/view?usp=drivesdk


Wiring Diagrams 6-3. page 78

https://drive..com/file/d/0BxZVixvKOy5sdm12UXBlQVVvTlE/view?usp=drivesdk
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[svxcess]

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Glove Box Removal Instructions

http://www.subaru-svx.net/forum/show...19&postcount=1


http://www.subaru-svx.net/forum/show...55&postcount=2
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[johnsvx]

Wow, much appreciated! I'll definitely be using these.

[John1]

You can find some instructions here. https://www.allicdata.com/products.html