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Discussion Starter · #1 ·
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I'm installing a '99 3.2L. I would like to try and start it before I proceed with tranny install.
Everything is connected (or so I thought). Turn the key to ON, lights in instrument cluster come on, hit START...nothing.
I checked the circuit and there is no power feeding the starter relay.
I checked the main 80A and 50A fuses, good. I checked C1 fuse, good.
1. Does the PCM need to be connected just to get power to starter?
2. Is there a neutral safety switch?
 

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The Neutral Safety Switch is part of the transmission Range Mode Switch (RMS). The RMS has to be in the Park or Neutral position to get power to the Starter Solenoid Relay. Additionally, the Anti-Theft module has to be in the not alarm state to complete the circuit ground. You will have to jumper around the RMS and Anti-Theft to get the Starter Solenoid Relay to energize.
 

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Discussion Starter · #3 ·
Rather than jumper for the mode switch, the tranny is just lying there. I'm thinking I can set it in front of the vehicle, wire it up, and still have plenty of slack to connect harness terminals, which I believe are the ones behind driver side headlamp. Just need to make sure I got the mode switch in Park.
I'm curious why I should consider the Anti-Theft module. (?) Wouldn't that already be tied into the body harness? I haven't located the AT module yet to confirm. The WSM shows it, best I can tell, drivers side by fuse box. But the direction arrow at bottom points FWD? Wierd.

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I'm curious why I should consider the Anti-Theft module. (?) Wouldn't that already be tied into the body harness? I haven't located the AT module yet to confirm. The WSM shows it, best I can tell, drivers side by fuse box. But the direction arrow at bottom points FWD? Wierd.
A relay located on the Anti-Theft module circuit board is part of the engine cranking circuit, in series with the Neutral Safety Switch.
 

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I thought 99 Troopers were 3.5L only and the rodeos were 3.2L.
 

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Discussion Starter · #6 ·
Perhaps you're right. The body is badged 3.5L. I'm putting in the 3.2L + PCM because that's what I have available. I believe the 3.5 is just a stroked 3.2.
 

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Discussion Starter · #7 ·
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So, here's the setup to try and test start. I'll add split loom to the harness prior to install.
This was the harness which was on the pallet with the tranny in the barn. With the exception of O2 sensors, all terminals found a home.
I ran the black/blue/green terminals up and tied them into the '99 Trooper engine bay harness.
But....Houston, we have a problem.
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The blue and green went together fine. Although I haven't checked to see if wire colors align.
Then I got to the black terminal...
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Why would the black terminal for a '99 Rodeo not plug into a '99 Trooper harness ???
Blimey.
 

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View attachment 120015
So, here's the setup to try and test start. I'll add split loom to the harness prior to install.
This was the harness which was on the pallet with the tranny in the barn. With the exception of O2 sensors, all terminals found a home.
I ran the black/blue/green terminals up and tied them into the '99 Trooper engine bay harness.
But....Houston, we have a problem.
View attachment 120016
The blue and green went together fine. Although I haven't checked to see if wire colors align.
Then I got to the black terminal...
View attachment 120017

Why would the black terminal for a '99 Rodeo not plug into a '99 Trooper harness ???
Blimey.
There are significant differences between the 99 Trooper transmission /RMS wiring and the 99 Rodeo wiring. You will have to make modifications to the wiring to connect the Rodeo transmission/RMS, it will not be plug and play solution.
 

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Discussion Starter · #9 ·
Ok. The transmission component wires (colors) are fairly easy to identify. Not so for the engine bay harness.
I currently don't have a book or diagram which explains what each wire is for on the blue/black/green terminals. I'm working on it.

In the meantime, I'm heading to the salvage yard, back to the '99 Trooper. I'm going to try and figure it out from the transmission harness on it, maybe pull it.
 

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Discussion Starter · #10 ·
Did it.
Got the donor 16-pin blue/black/green terminals. I was all set to remove the entire transmission harness but my salvage yard is like the wild west. Everything is on the ground and surrounded by vegetation. Not really interested in propping a vehicle up on some old wheels that may be laying around. Just too sketchy. If I get pinned it may be a few months before somebody came looking.
So, I came away with just the terminals.
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Discussion Starter · #11 ·
Very quickly, I realized I needed to understand what wire/color ran to what component.
So, the harness was de-pinned, de-bundled and all the information recorded.
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A $10 set of ~40 de-pinning tools off Amazon was very helpful for de-pinning these terminals.
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I created a map of the case connectors just to understand and future reference.
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Discussion Starter · #12 · (Edited)
Ok, so it was probably quite amusing to read that I was just "plugging in" and hoping for the best. Yep, pretty silly.
Buster tried to hint at it but- it took doing... and failing, to understand.
The 99 Rodeo harness is different from the 99 Trooper harness. Forget that they both have blue/green/black terminals and might even have the same number of pins. There are different wires and different pin locations.
So...... after many, many, many trips between the computer, the circuit diagram, the vehicle... I created a spreadsheet to aid anyone trying to make a jump between a 99 Rodeo tranny harness and a 99 Trooper engine bay harness. This may apply to some older trannys.
The terminals between the two harnesses are known as H-10 = (blue), H-11 = (black), and H-9 [Rodeo] / H-53 [Trooper] = (green).
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On a side note, the tranny harness I have had a 12-pin black terminal, which might be for a manual transmission. Not sure, but possible. It was a barn find so, you know. Get what you get.
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Discussion Starter · #13 ·
Almost there.
The anti-theft module won't let it start. The hood switches are all open and who knows what else. I decided that as this vehicle is 20+ years old, there's not a whole lot of theft concern. So, I disabled it. The module is in the center console under the radio. A jumper between pins 23 and 28 effectively grounds it which allows the ignition to start.
The jumper is temporary as I'll probably join the blue and black wires and remove the box.
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Discussion Starter · #14 ·
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Ok, so here it is. The setup. I was able to cycle through all the gears and instrument cluster confirmed. I'm very confident that the spreadsheet data (above) is correct.
I got to this point yesterday and it would NOT start. I was thinking the PCM was bad, even though I heard that they rarely are. I started a thread in this forum on bench testing a PCM. In a nutshell- can't be done in your garage with a multi-meter...
So, I started running through the circuit diagram looking for something. Also strange was that the diagnostic connector (OBD) wouldn't read the PCM. Just kept saying... scanning.
I should probably add at this point that this thread started off a bigger thread where I'm trying to put a '99 Rodeo engine into my '00 Trooper. Yada yada yada, I found the problem. Bitten in the butt again for plugging in connectors that look the same but are different. In a nutshell, my engine fusebox/relay harness was still the '00 Trooper, but plugged into was a '99 Trooper engine bay harness. Black and blue 16-pin connectors, better known as H-41 and H-42, right behind the RH headlight. Lo and behold, they are different. Between 1999 and 2000 model years, Isuzu changed just about everything wiring harness.
Luckily, I had already pulled one off the '99 salvage yard Trooper and had it by the ready. A few hours later, one harness out, the other harness in,.... turn the key....
It starts and runs !!!!! OBD scans!
I didn't run it long because it has no exhaust connected. But it ran.
Also because the engine wants to lean back slightly, resting against the firewall. I had to use a short 2x4 just to keep the flywheel from making contact with anything.
But it ran.
 
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