Builds bcomnes' 1991 3FE FJ80 Build (1 Viewer)

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I had to come up with a new CDS fan schematic:

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So the cabin switch is basically a kill switch, and the switch LED becomes a pressure switch indicator that will always run. This gives me an idea if the fan will be on or not, depending on the state of the AC pressure. I like this design, but am still unhappy that I don't get the shorter after-run behavior others are seeing.
 
Hard to tell from your pics and diagram, but hopefully you are not running 12v through the pressure switch, it should go to ground. FWIW - my fan on the hottest days in AZ or UT runs for 1-3 min after shutoff. My AC is ice cold at idle during these temps too.
 
It’s 12v but through the low current side of the relay To ground and the bulb in the cabin switch. Afaict, the bulb and low current relay keep current nice and low through the pressure switch.

Fan current goes through the high current side of the relay to ground.
 
It’s 12v but through the low current side of the relay To ground and the bulb in the cabin switch. Afaict, the bulb and low current relay keep current nice and low through the pressure switch.

Fan current goes through the high current side of the relay to ground.

I would switch that to take the relay to ground. The switch inside the cab should take it to ground too.
 
I would not have any voltage going through the pressure switch. If I remember right, its a ground going through the pressure switch from Toyota and I prefer to match how Toyota has done it. That is why I would match that using the two extra pins. Again it's hard to tell with your wiring diagram the best way to solve it, but I would use the pressure switch along with the in-cab switch to go to ground in order to activate the relay. It ultimately may not matter, I just preferred to make it match how it was wired. I also would be concerned that having both voltage and ground running through the pressure switch at the same time as that might cause problems, but that is based on nothing other than a hunch as I haven't cracked open a pressure switch or referenced the FSM for this specific thing.

Here is the thread I followed to do mine and its been trouble free for years - the first post explains how to ground everything.
 
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I’ll re-review that. When you say “going through”, it makes me think of current (the part that causes heat), not voltage (the potential difference from positive to negative or across resistive components or loads), and I think that’s what I’ve achieved by using the low current side of the relay with the pressure switch, and I’m not sending fan current through the pressure switch. A relatively low current should be all that’s flowing through the mechanical pressure switch.

But someone correct me if I’m wrong, there aren’t lower voltage power sources used elsewhere in the car is there? The oem relays work off 12v on the control side and don’t need a load resistor right?

Im going to do some measurements on the other relays and make sure their control side are running at 12v corroborating my understanding that there is no need for a control side resistor.
 
Ok so I just re-read that and they suggest going from the ground side of the aux control relay to the pressure switch to ground. I have my pressure switch in front of the relay. Since it’s just a mechanical switch (0 ohms for the most part), and it’s in the same Series circuit as the relay, the pressure switch should have the exact same current run through it in either position, and not affect the voltage the relay ‘feels’. I still want to confirm the other relays are running at 12v. I suspect the relay heat is just coming from this fan pulling some current, though everything is under the 20A fuse and the relay is rated at 22A. I’ll take a current measurement too just to double check that.

EDIT: Oh I also forgot to mention, I did try running it with the pressure switch after the relay, much to the same outcome. I switched it around to make wiring simpler with the more complex cabin switch wiring that included the pressure indication light. In terms of switching behavior or relay heat, it seemed to behave the same.
 
just measured the resistance across the control side of the relay and got 72 ohms, meaning that if I run it at 12v I’ll be running at 0.166 amps. Not terrible. I’m going to travel with spares and if an aux fan relay burns out the car still drives.
 
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Gaia Track:


The Gaia app tends to crash a lot, but when its working, its a great view to have pulled up on CarPlay, showing both my planed track, and my current track.

Overall, the 91 did great! 0 problems, and performed well. No overheating symptoms, and I made good use of my new CDS fan.

I do think I might have an exhaust leak somewhere though, as slow points, with the AC going, I could smell exhaust in the cabin.
 
Damn, so my Camery antenna mod fix failed today. Actually it failed a while ago, and I think its just been holding on barely.

Gonna bite the bullet and just go for a new assembly, because I'm pretty sure I bought the last camery antenna cable off Ebay.

Still planning on finishing up the Cat plate soon.

Also finally bit the bullet and bought a full set of LEDs for the car, inside and out. Will post results of that order soon.

Also, found the location of that monolith in the desert. Thinking of going for a visit.

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Installed exterior LEDs and flasher yesterday, everything working fine except the tail light, which goes out whenever I use the brake light. Going to troubleshoot more today. More info below


UPDATE:

Made some progress over here:


TLDR: the 1157 LEDs seem sensitive to relay noise, and I had a vamp tapped towing connector relay on my tail lights. I removed it and it improved the situation to a working solution.
 
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Full set of interior and exterior LEDs for a 91 FJ80 arrived from superbrightleds.com (except for a couple wedge types that were out of stock, and high-low beam pairs).

Opted for LED color matching over color filters, and warm white LED where a white incandescent was used before.


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Great thread you have going here! Which bulb did you order for the map light up by the sunroof controls?
 
Great thread you have going here! Which bulb did you order for the map light up by the sunroof controls?
Thanks!

I used a BA9s from super bright LED, warm white. Its not that much brighter than incandescent, but there is an improvement in output, it runs way less hot, draws less power, and still keeps the feel of the incandescent mostly.


For the rear two lights, I used the festoon variant:

 
Photos of some of the stuff I removed yesterday as well.

91 towing package relay? Is this OEM? No Toyota marking at all. The black box had two relays and a potted circuit board on it with some capacitors. Window sticker for the car mentioned a towing package, so maybe this is something the dealer threw on? Could also have been a PO. Either way, a 3FE ain't towing s***.
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Rear 'sub'. Totally crusted out. Looks water damaged. I could barely feel the speaker cone move when the audio was running. Unclear if just the speaker or also the amp was having issues.
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'Sub' amp. Would be great to get something simple to replace these with. Same connector as behind the radio, so I should be able to get a Toyota breakout connector to connect to something more modern.

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Thanks!

I used a BA9s from super bright LED, warm white. Its not that much brighter than incandescent, but there is an improvement in output, it runs way less hot, draws less power, and still keeps the feel of the incandescent mostly.


For the rear two lights, I used the festoon variant:

Thank you ordered!
 
Anyone recommend a good relay/fuse block for adding 3rd party accessories (radio/lights etc) that fits well in a 91 engine bay?

Also, I smashed my engine fuse box lid/cover thing closing my hood on it. Looking for a spare if anyone can part with it for a few bucks.
 

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