Trans. wiring harness

OK,
I've read "Everything you ever wanted to know about the AW4" by Kastien.

I have yet to find my problem with the swap. I have an 88 MJ that used to be a 5 speed (Peugot), the "new" 92 AW4 is in and bolted up. I'm going to the yard in the morning.

The MJ does not have the same NSS wiring...4 wires instead of 6. It does not have the 7 pin connector to the TCU. There is no automatic tranny wiring in the whole Jeep.

Can anyone tell me exactly what I have to get to make this plug in.

I have:

ALL the mechanical eqipment including brackets and a Renix throttle body. I have a Renix flexplate, Renix CPS. I have an HO TCU (if I need a Renix TCU someone tell me).

I need:

A harness with the plugs for the 7 pin AND the NSS that will plug into the ECU (do I need a Renix ECU too?).

The Automatic brake pedal and associated wiring.

I have 2 almost intact donors...one is a 92, 4.0 yada yada.
the other an 89, 4.0 etc.

Can anyone give me a shopping list for the yard. I gotta be there at 8 am because it's supposed to be 103 here tomorrow and I can't even THINK after it hits 90.

Nothing?? Anyone?

I believe the TCU on the early models is stand-alone.

You will need a TCU (behind the glove compartment?), and the wiring harness for the AW4 from the 92.

The Haynes manual has a pretty clear line diagram in the back showing the TCU/AW4 path.

HTH

I don't believe the 4 wire connector is an NSS connector, especially with a 5 speed originally installed - that's probably the connector for just the reverse light switch and maybe the part time indicator lamp switch, not too sure how that's routed on a RENIX.

The wiring for the auto is sorta-kinda built into the engine bay harness, but not too much is involved, most goes straight from the TCU to the transmission. The TCU is under the dash on the passenger side and the harness goes through a large rubber plug, joins the main harness, then branches out again after a few inches and goes to the NSS and harness for the solenoids and output speed sensor. IIRC the only wires that go elsewhere are for ignition switched +12V, the TPS signal (you will need to switch to the cheaper, dual-element RENIX TPS for autos and add the appropriate wiring for the second element), the brake light switch sense, a ground, and perhaps a few others I'm forgetting. I know clawson has posted more detailed info on how he got his auto swap to work - he basically skinned an engine bay harness on an appropriate year donor auto, ripped all the auto specific stuff out of it, then spliced it into his manual harness.

Also, I found that torque converter I meant to send you forever ago when I fixed the jeep it was sitting in the back of - my apologies on never sending it, the post office didn't like how it was leaking some trans fluid. Should I plastic bag it, repack it, and send it or are you all set at this point? Shipping's on me if you still need it, I should have sent it quite a while ago.

The Torque converter, I just decide to buy a new one from Rock Auto. It wasn't bad $$ wise, no worries. Like I said everything is in place and bolted in EXCEPT the wiring
The NSS on the 5 speed, you're right, is just a reverse light switch. The TPS double output wiring was already there, I just got a different throttle body with an auto TPS.
Anyway I have both a RENIX TCU and a HO TCU. I have the wiring harnes for a 90. I was waiting on whether I should get an ECU for the AW4.

So essentially I was thinking I could do what you say clawson did. Just dissect the harness I have, lay everything on the shop floor and map out where it all goes.
Of course my 88 has the C101 connector and niether of the harnesses do. But the connectors are all the same. I just don't know the big questions and I get conflicting answers (which is why I'm beating this to death).

Do I need a RENIX or HO TCU. Do I need a RENIX or HO automatic ECU. After that I can figure out where everything goes.

...and Thank You.

You don't need any new ECU - the ECU on RENIX barely even realizes the transmission is there, only for diagnostic purposes as far as I know. Even on HO (through 96) it's almost entirely separated, and after that, it'll run fine, and will just set a code saying it can't talk to the TCU and doesn't know if anything is wrong with it.

I'm not sure if you need a RENIX or an HO TCU - a RENIX will certainly work, I'm not sure if they changed the TPS signal scaling for the TCU output from RENIX to HO. I know the RENIX sensor has two outputs, one going up in voltage as the throttle opens and the other going down, one for the TCU and one for the ECU, and the HO only has one output, but I'm not sure if it goes up or down (I think it goes up as the throttle opens...) and I'm not sure which of the RENIX outputs is more similar to it. So if you use an HO TCU you may need to tap the ECU output on the TPS instead of the TCU one, and it may still not be exactly perfect. Other than that, they are mostly the same.

Oh, the gear ratio for OD changed very slightly between 21 and 23 spline models, but that shouldn't really affect the shiftpoints set in the TCU either way, and will be barely noticeable even if it does.

So basically - aim for a RENIX TCU if you can, if you can't, get a 91-96 HO TCU and the plug that fits it (iirc they are slightly different from RENIX plugs, with the same pinout, just the plastic shell shape changed a bit) and we'll go from there.

I don't agree. If he is using a Renix CPS and flex plate, he MUST use a Renix ECU, the CPS changed from 90 to 91, they are entirely different, and are not compatable.

The Renix ECU uses a different TPS than the 92 HO. It is made up of 2 independent TPS sensors attached to each other, and the Renix TPS second half talks directly to the AW4 TCU.

In 91 the HO TPS is a single unit, and the it talks only to the ECU, and then the ECU talks directly to the AW4 TCU.

I also think the TC lock up brake sensor set up changed between 90-91.

PM Lawsoncl, he is the AW4 electrics expert here.

I never said anything about the flexplate - he's using a RENIX jeep with a RENIX flexplate, so I assumed a RENIX CPS and ECU were already installed and he was asking if he needed to switch to an HO ECU to make the transmission work, to which the answer is no, which we agree on.

You're incorrect about the way the TPS signal gets to the TCU on HO - they redesigned things so that the TCU and ECU use the same signal, and it's hard wired to both. There is no TPS signal communication between the ECU and TCU, the TPS is hardwired to the TCU as well.

Oh, and as for the brake pedal - you don't need to buy a new one if you don't want to, just unbolt the clutch pedal and leave the rest how it is. The brake pedal will be a bit narrower but that's ok if you are ok with it.

You *might* need a new brake light switch, since the TCU also reads the signal from the brake light switch to determine when it should unlock the torque converter. Not sure if you have that on your list already.

kastein said:

I never said anything about the flexplate - he's using a RENIX jeep with a RENIX flexplate, so I assumed a RENIX CPS and ECU were already installed and he was asking if he needed to switch to an HO ECU to make the transmission work, to which the answer is no, which we agree on.

You're incorrect about the way the TPS signal gets to the TCU on HO - they redesigned things so that the TCU and ECU use the same signal, and it's hard wired to both. There is no TPS signal communication between the ECU and TCU, the TPS is hardwired to the TCU as well.

Click to expand...

OK, but His first post said this:

"A harness with the plugs for the 7 pin AND the NSS that will plug into the ECU (do I need a Renix ECU too?)."

Second post:

"Do I need a RENIX or HO automatic ECU"

So I assumed he did not have a renix ECU yet. And I have no idea what the answer to his second question is, because I have never considered that issue before!!!! Scratching my head now on it.I think I agree with you, that the Renix ECU did not care if it had a manual or automatic transmission, but the HO 91 I thought did, perhaps it is 96 OBD-II that did?I may be thinking of 96 OBD-II changes in the TPS to TCU area, but IIRC, Lawsconcl told me a long time ago that the 91 TCU gets its TPS data from the OBD-I 91 ECU, not from the TPS directly. Perhaps my memory is faulty, and it is the 96?I do recall Lawsoncl mentioning that the TPS signal to the TCU on the 91 versus 90 is flip flopped I think, which you just mentioned?What about the Vehicle speed sensor, did it go from mechanical to electric in 91 or 96? I vaguely recall a possible issue there, but that could be the 96 as well?I was trying to clarify that he needs to stay with a Renix ECU, if that was not clear to him.

And I finally recalled the brake switches issue, I think. The brake switch is a double switch, the second pair of contacts go to the TCU for TC lock up (IIRC), unlock signals from the brakes (and there is a diode in the wiring too, and a fuse to the TCU). IIRC the upper white combo vacuum/electrical switch is for cruisie control?

None of them care, but on 97 and later, the ECU will flip a code if you take the TCU out because it can't get status updates/diagnostic info from it. Will still run just fine.

90 to 91 is the VSS mechanical to electric switchover - that apparently affects the ECU (I've heard people say it will run funny without the electric VSS, though that's not my experience, I didn't test it for long so I'm not sure) but won't affect the TCU at all. The output speed sensor will, but that's directly connected to the TCU and nothing else, and only changes from 97 to 98.

I have the original ECU installed still (for the manual).
I have the two sensor TPS
I have the TCU that came with the Tranny.
I have the brake pedal with the HO wiring to go to the TCU or is it the TPS.
I have a RENIX automatic AW4 TCU and ECU harness now with the correct plugs for the NSS and 7-pin.
The harness has all the RENIX sensor connectors on it. The VSS on the tranny is electric. All the wiring on the tranny is in good shape and only hooks the harness thru the 7-pin connector.

As part of the harness I also have the injector connectors all the way to the O2 sensor. When I look at the harness I could easily strip it out and use just the TCU relavant wiring...but some of that also goes towards the coil wires, dignostic connector. I just wonder if I'm WAAAY trying to overthink this.

You guys have apparently had experience with this and so I REALLY appreciate your knowledge. Good thing this is a shop project and isn't my DD. On the job (on the project) training works for me and I feel like a dope when it comes to something I've never done before. I hope to get working on it soon...right now it's just way too HOT...

Thanks again.

Well I have not done anything but R&R the AW4 transmissions, and drive train and study it in chats here from others, never an HO/Renix swap like you are doing.

Won't the electric VSS be a problem for the Renix Dash gauge set up, MPH and ODO?

Will you have cruise on it ever?

Cruser54 should know for sure if the manual Renix ECU is the same as the AW4 Renix ECU. He was dealer service manager....

I don't think the brake light switch goes through the ECU, but the dual one (used with AW4 rigs) does have a second pair of wires that talk to the TCU to unlock the TC, so I am told!!!!

No, it will never have cruise...not while I own it anyway.

Right now I just have a brake light switch, no info to the trans just a on/off switch...but the "new" pedal, has the switch for the TCU/TC lockup. There is also wiring from the tranny TO the T-case. I've also eliminated/locked the CAD axle so the 4x4 is all just linkage...if the light works or not, I don't care. I'll be putting new, to me, axles on it in the fall (even I can handle that!!).

I kept/swapped the gear/cable set-up for the speedo. I jumped the NSS. It works fine, it starts, runs and makes it up and down the street, shifting manually. Just trying to finish it up the RIGHT way.

I'm not a mechanic by trade, I'm NO kind of engineer (especially electrics) I'm a chef/food service guy. I'm just too cheap/broke to take it to a mechanic. I would like some of Cruiser's input too. More info is better...me trying to do it on my own, scary!!

:cheers: