Does the fuse block go bad?

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bgim

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Nov 16, 2007
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I frustrated trying to get my tail lights and instrument panel illumination working. First the tail lights were out, but not the instrument panel - traced that to a rusted and broken wired due to hole in the body behind LR tire.
While taking apart the steering column covers and Driver side kick panel, I lost my instrument panel lights, and now with the tail light wire fixed I still don't have tail lights or instrument panel illumination.

I can get the tail lights, rear side marker lights, and license plate lights to come on by applying 12V to the green wire at the harness that connects it to the fuse block, so all the wiring and lights on the tail light circuit from the fuse block back, including the tail light failure sensor, appears to be working.

Here's the problem: when I pull out the tail light fuse and apply 12 V to the non-grounded side of the tail light fuse socket no lights come on.

And nothing seems to be reviving my instrument panel lights.

Several times I tried different fuses. even tried replacing all the fuses on that block.

I also have a large stray connector near the steering column. It seems to match the O1 connector in the Toyota Electrical Wiring diagram manual, but that one is supposed to be on the passenger side. I can't see anywhere for this connector to attach, can't tell if its important or what it does.

Is it possible that I have a bad fuse block?

Anyone got suggestions, or at least want to commiserate? Thanks.
 
IwantMKIII

IwantMKIII

WVU MAEngineering
Jun 12, 2007
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i don't mean to undermind you here but did you bother to check the intensity adjustment on the underside of the dash to make sure it was actually on?

I only ask because many of us have done this, tore apart the dash thinking we messed something up, only to find it was the damn switch that accidentally got turned off.
 
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bgim

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Nov 16, 2007
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I did check the dimmer, but I'll take one dummy point: the "grounded sided" of the fuse is the load side, and everything works with voltage applied to that. Now my problem is that the relay won't come on, though the relay tests good, replacing it doesn't help. The switch itself seems to be good, because activating the tail light switch changes the electrical properties of pin 2 of the tail light relay socket. Strangely the resistence to ground goes to infinity when the tail light switch goes on. I thought the resistence should go down to allow current to ground to activate the relay. This brings me to the Integration Relay #2, I think. Any experience with this? How to find it, test it, etc.

How about with the unused large connector by the steering column that seems to match "O1" wire to wire harness in the TEWD, but has no evident place to hook it up. Is that normal?

Thanks, and sorry for the goof in my first post.
 
3p141592654

3p141592654

90T
Oct 11, 2005
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You're going to have trouble using your DMM to troubleshoot the relay control line going to integration relay #2 because it is an open collector switch.

Instead, pull the taillight relay out of the fuseblock and jumper terminals 2 and 4. That should turn the taillight and instrument lights on.

(Be careful... if you short pin 4 you will blow a fusible link and that is a pain to fix.)

Assuming that worked, put the relay back in, disconnect integration relay #2 and ground the green-white wire going to relay control. The taillights should go on. If not , the relay may be bad or the wiring.

Report back your results and we can think about the next step.

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=062
 
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bgim

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Nov 16, 2007
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3p141592654;1004712 said:
You're going to have trouble using your DMM to troubleshoot the relay control line going to integration relay #2 because it is an open collector switch....
Click to expand...

Thanks. The lights work with terminals 2 and 4 jumpered. The relay works with the control pin grounded, out of the car. I haven't found the Intergration relay #2 yet, so I haven't done exactly the test you suggest, but the odd reaction to the DMM test current on the Ohm setting suggests I am connected to the "open collector" circuit, and it is changing state when the tail light switch is on.

Now I could use help locating the Integration relay #2 - Sorry for asking info in the manuals, but the TEWD diagram is a bit vague, and it would save me some time to get a tip here. Then I need help figuring out what the heck to do with the IR #2 when at long last we meet. I could put in an extra switch to the dash to activate the taillight relay, but what fun would that be when I've got a hand-me-down electronics shop at my disposal and a deep unmet need to avoid chores by looking busy all evening? Thanks for helping me with this.
 
3p141592654

3p141592654

90T
Oct 11, 2005
3,816
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Thousand Oaks, CA
Good news, it is looking like the IR#2 may be bad.... and as I recall there are a couple of large power resistors on that board that are known to fail so it could be an easy fix.

How good are your soldering skills?
 
Poodles

Poodles

I play with fire
Jul 22, 2006
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damn I hate that box LOL

Took me forever to track down my wiring issue, and it was the IR#2... the TSRM wasn't an help in tracking the issue down, I just grabbed one of everything from a parts car that was part of the headlight circuit and started swapping parts...
 
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bgim

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Nov 16, 2007
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jetjock;1005860 said:
Integration Relay 2 is located in the area behind the fog light switch panel. Square box about the size of a pack of cigarettes. Blue in color iirc. It's connector I-12 here:

http://tinyurl.com/3nz35s

Also here, labeled as "light retractor relay":

http://tinyurl.com/3rbfz6
Click to expand...

Thanks. The Light Retractor Relay i've seen, now i get it. Thansk for the diagrams. I'll be good from here.
 
B

bgim

New Member
Nov 16, 2007
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3p141592654;1006174 said:
Good news, it is looking like the IR#2 may be bad.... and as I recall there are a couple of large power resistors on that board that are known to fail so it could be an easy fix.

How good are your soldering skills?
Click to expand...

Vaporized heavy metals? Singed fingers? I'm all there! If you don't hear back it means I'm good and it's what you said. Otherwise I'll let you know. Thanks again for the tips.
 
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