What are these extra connectors for? (1 Viewer)

[yooper]

There are three unused electrical connectors in the engine bay, on the right side wheel well hump near the firewall on my '99 100.
See the attached photo.

The black two wire connector is quite interesting. The wires are large, about 14 gauge. The hot wire is blue with a black stripe. If I could find out what switches this one it would be a sweet place to hook up some driving lights.

Does anyone know what these connectors are for? I've perused the FSM EWD book at length and can't figure it out.

 

[hkeller]

Those are probably for the AHC suspension system, which the use LX had, but the LandCruiser did not. It mounts right there.

 

[yooper]

Yeah that makes sense. So where does the big blue wire with black stripe go? Is it supplying power to something right there or is it sending power to something like the compressor in the back? It would be really cool if I could utilize it rather than running new separate wires for accessories I am adding.

 

[hkeller]

Good question. I am sure the pump that goes there in an LX needs significant power. Anybody got a meter?

 

[100 TD]

Get yourself an EWD for your model from techinfo site.
In the 2003 model the relay controlling the AHC is in the main relay box under the hood (probably the same for the earlier), no relay installed on mine, just a spare spot. I popped the relay box open and chopped the relay control wire and ran a new one. Then I put a fuse in the AHC spot and a relay in the spare spot and used it for my compressor control. IIRC the original vehicle spec calls for a 50A fuse, so the circuit is good for plenty of grunt. I changed it to 30A I think. If you find an EWD for your model, you may be able to chase the contol wire from the relay back to the cab somewhere and hook onto that wire for your control circuit. I expect it will run back to wherever the AHC ECU plugs in.

 

[100 TD]

I found a 2002 schematic, it shows a green with yelow stripe going from the relay to the suspension control ECU. Find that wire in the connector where the ECU plugs into the harness and power it and you will turn on the AHC relay and send juice down the Blue/black heavy wire. (after fitting fuse and relay that is)
Edit: Best get the 99 EWD though, there may have been some changes, also there is more than one green/yellow at the ECU

 

[100 TD]

Actually the schematic I have is from a 2002 LX470, so the LC may not have it in their manual, but as you know the wires are there. You may have to get a 1999 LX470 diagram to help you find the correct wires. Maybe Lexusben could help or someone else with a 99 LX who has a manual.

 

[yooper]

I said above that I've been reading my EWD. There is no AHC info in my '99 LandCruiser EWD.

I don't have a suspension control ECU or any AHC related relays, so powering that G-Y wire won't do anything I don't think. Thanks for looking though!

The best I can hope for is to find where the wire goes. Fewer new wires passed through the firewall is a good thing.

For example if it goes all the way to the rear of the truck it would be absolutely PERFECT for powering my Engel refrigerator, because the engine bay end of the wire is right where I'm going to put my second battery.

 

[100 TD]

I said above that I've been reading my EWD. There is no AHC info in my '99 LandCruiser EWD.

I don't have a suspension control ECU or any AHC related relays, so powering that G-Y wire won't do anything I don't think. Thanks for looking though!

My LC is the same, no AHC, but the wiring is all there as they use the same harnesses for the vehicles with AHC. This is why I said get hold of a LX470 diagram, it will show the wiring and where it goes.

The best I can hope for is to find where the wire goes. Fewer new wires passed through the firewall is a good thing.

PM me your email address and I will send you a 2002 LX470 AHC EWD, I expect it will be VERY similar to yours (98 to 2002 are very similar). Due to mine being a diesel and also a RHD I had trouble finding where the wire went so that is why I put a new one to the spare relay position . This allowed me to use the existing heavy wiring that goes to the AHC motor(the motor which I don't have) and hook up the compressor to it. This saved running wires and relays and fuses.

For example if it goes all the way to the rear of the truck it would be absolutely PERFECT for powering my Engel refrigerator, because the engine bay end of the wire is right where I'm going to put my second battery.

If you don't have a rear A/C, you may find there is already a 20 Amp fused wire heading down the back that you could power your fridge from, however if I was installing a second battey I would run a much bigger wire to the back for the fridge and any othe later mods.

 

[yooper]

I sent you a PM, thanks! Where is the AHC motor? I'll look there for the other end of the wire...

I probably will end up running an 8 or 10 gauge wire to a junction box in the rear for accessories from the second battery.

 

[100 TD]

I sent you a PM, thanks! Where is the AHC motor? I'll look there for the other end of the wire...

You and I don't have the motor, but it would plug into the heavy Blue/black and White/black wires you have under the hood. The Blue/black will most certainly come from your Relay/fuse box under the hood.

The wire you need to find is the relay controil or coil wire that goes to the AHC relay (green/yellow)

Look at the photo in post 9 here
https://forum.ih8mud.com/showthread.php?t=86714&highlight=relay

Does this look like your fuse box, it appears there is a 50 amp fuse second up on the right, from the photo is looks like the cover says AHC. You will possibly have a spare spot for a fuse to go in there or a fuse may already be there. Then you need to look at YOUR relay for a spare spot for the AHC relay.
Here is a picture of MINE at post 8

https://forum.ih8mud.com/showthread.php?t=68872&highlight=fuse

It is different than yours but shows the spot the AHC relay would plug into if it had AHC. I purchased a factory relay and put it here. Does your relay box have a spare spot? Does it mention AHC on the cover of the relay box?

EDIT: AHC EWD emailed

 

[yooper]

Yep, my engine bay fuse/relay box says "AHC" on the lid and that relay spot is empty.

The three wire connector in this picture has a green/yellow wire. So if I stick a relay in the box and send 12V to this green/yellow wire I will get power to the blue/black wire? !

EWD received, thanks! Will peruse now...

 

[yooper]

OK, looked at the EWD you sent. So where physically is the suspension ECU in the LX? Is it in this same location, i.e. does the connector in my photo connect to it? If so then I am set. I can pop in a relay, run a switch to my choice of power and this wire, and hook my driving lights into the blue/black wire....

I need to get an OEM relay to test this out...

 

[100 TD]

.........The three wire connector in this picture has a green/yellow wire. So if I stick a relay in the box and send 12V to this green/yellow wire I will get power to the blue/black wire? !

NO

OK, looked at the EWD you sent. So where physically is the suspension ECU in the LX?

That's what you need to find out! Maybe Hoser, Jim Chow or someone with an LX can help. From what I can see from the 2003 info it is behind the dash on the right of the steering column, so if you stick your head under there there will probably be a few spare connectors floating around on the loom, but they may be hidden and hard to find. This is why I ran a new wire to the fuse/relay box. (as well as mine being a RHD diesel these diagrams don't match up)

Is it in this same location, i.e. does the connector in my photo connect to it?

I expext it does, however it is not the wire you want, I expect it will be from the pressure switch, but if you find the connector it goes to under the dash, the other Green/yellow that controls the relay will be there as well. That is the one you need to find.

If so then I am set. I can pop in a relay, run a switch to my choice of power and this wire, and hook my driving lights into the blue/black wire....

I need to get an OEM relay to test this out...

 

[Jim_Chow]

The AHC ECU is in the dash.

I took a look at the 03 LX electrical FSM. It has a section that has all the connector types on the vehicle w/ the color and mapping to what the connector is for and I think the P/N. Anyways, I could only find 3-4 black, oval-shaped 2-pin connectors on the vehicle. The biggest one is for the AHC motor. OTOH, the schematics show the two wires feeding this plug are blue (L) and white w/ a black stripe (ground). I took a look in my engine compartment this morning and confirmed the colors. There are a number of plugs for the AHC, one being a grey one like you have pictured. BTW, this wire connects to the AHC relay (relay box), which goes to a 50A fuse.

The only blue w/ black stripe wire in the AHC system I could find in my FSM is between the switch in the center console to the ECU in the dash.

 

[Traveling]

Since I am fighting trying to reset my AHC pump, I feel these pictures could help you to understand how these 3 connectors worK.

It seems there could be many conflicts in various numberings or EWD colors between Lexus/Toyota or even between LC's.
Mine is a 2000LC100 with AHC ( called in E.U as HDJ100 4.2l TD VXE), and seems to have the same colour coding as yours.
I do not have the AHC EWD (got only the UZJ manual), so I had to chase after these wires with my meter.
The Black connector with the two large wires is feeding the AHC pump electric motor.
The Line (+) is Blue with black stripe , while ground is White with Black stripe.
The Line is definitively coming directly from the AHC relay ( meter reading O Ohm); I cannot commit the line is not feeding other equipments , but i do not see why it should ( HP pump justifies full use of one relay, and no other AHC equipment is running with huge power when pumps run ).The AHC fuse next to it is 50 Amps, and directly linked to AHC relay.

The black connector with 3 smaller wires ( main color green , red, red) is likely a pressure switch feeding datas to the suspension ECU, as it is set on the discharge plate of the HP pump, just below the HP pipe.
The grey connector with 2 smaller green wires is certaily supplying infos to the suspension ECU as it is set on the back of the pump ( not sure for what purpose yet).
I found the suspension ECU behind the dash inside the cab; not at all comfortable to work!! I twisted my neck so will wait for few days to then check if the smaller wires are connected to the ECU and to find which wire is going from the ECU to the command of the AHC relay.
If anything , I"ll let know.

 

[yooper]

Very nice Traveling, thanks! Can you tell us the part number on your AHC relay?

Today I had a minute to check and I found that the harness that I got with my driving lights from mot reaches to and plugs right into the connector with the Blue-black and White-black wires! So if I can make this work, the only wire splicing I'll need to do is for my switch in the dash.

I'll have my dash apart in the next week or two for a stereo install. I'll try to find the Green-yellow wire then...

 

[Traveling]

Well, I don't know much about relay specs/denomination; so I tried to upload a photo; too bad I am already over my band allocation!
So here is what is stamped on one side of this relay:
ABS(TRC)RELAY
TOYOTA
88263-24020
056700-9810
12V
DENSO
MADE IN JAPAN

If you cannot make it with that , I may still check the official TOY P/N on my EPC disks ( but just realised they work on WIN98s , and it looks like one of my monsters has "made my computer run better" by getting rid of.... Windows 98).

BTW, I am prettty well loaded with huge amount of computer stuff and hard copies for TOYOTA 4WD that I accumulated since my first BJ40; but of course I just miss infos/datas on LC100 w/ AHC , and I am working rigth now on that
.
It seems you have a AHC EWD; is that possible you could you mail me a copy ( I am really like a mushroom in the dark without it!)

 

[yooper]

I think 88263-24020 is the part number, and it's the ABS relay?

So you have two relays that are labeled "ABS relay"?

I think 100TD has the whole EWD. He just sent me one page.

 

[100 TD]

I think 88263-24020 is the part number, and it's the ABS relay?

So you have two relays that are labeled "ABS relay"?

I think 100TD has the whole EWD. He just sent me one page.

Just checked the part number for the relay, it is the same for my 2003 vehicle, I just got a paint marker and wrote "Compressor" on top of it to make it stand out.
(I think there were 2 ABS relays in there, different colors IIRC)
I downloaded FSM and EWD from http://www.techinfo.toyota.com/ , but the AHC wiring diagram is from a 2002 Lexus as the LC does not have the AHC (but has the wiring as we know). I don't have any other Lexus stuff, but it is all available (Lexus/Toyota/Scion) and now Natergator has made the download process really easy instead of having to click 1400 seperate files I believe you can now download the lot in one hit. https://forum.ih8mud.com/showthread.php?t=128021