700R4 Lock Up Converter Talk and Diagnose

[89Suburban]

That's the terminal "Oh ****!"

You damn right, I **** myself. I had the boat loaded and kids half way to the ramp and I said "watch this kids!!!".

Half the power went out on the truck and I thought I was phucked. On top of being 96 and 96 humidity trying to find a blown fuse with cars wizzing by and hot miserable kids, lol....

 

[Jims86]

I grounded terminal f driving in 3rd gear and it blew the 20 amp gauges/idle fuse.

Yeah....wtf?

 

[Jims86]

Ok...can you get to the back of the diagnostic connector and tell me what color the wire is going into pin f? If manually grounding it blew a fuse, then the computer would blow it every time lockup is commanded.
Do you have a test light that you can stick in there?
Here Bee the diagram iffin anyonenis interested.
This diagram has both the lockup for the 700r4, and below it is the downshift control for the 400.

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[89Suburban]

These are ****** pics, the wire on "F" is tan/white stripe.

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[Jims86]

Yarp, thats the one.

 

[89Suburban]

Hmmm....

 

[Jims86]

What did you ground it to?

 

[89Suburban]

The dash metal.

 

[Jims86]

****....I'm afraidmto make any more suggestions. Havebyou tried keeping your foot on the accellerator to maintain 40mph, and tap the brake with the other foot to see if you hear a difference in the engine sound?

 

[89Suburban]

****....I'm afraidmto make any more suggestions. Havebyou tried keeping your foot on the accellerator to maintain 40mph, and tap the brake with the other foot to see if you hear a difference in the engine sound?

I'll try it tonight.

 

[crazy4offroad]

I can tell you when I took apart that TH350C the switch wires in the trans pan had gotten so brittle the insulation cracked off them with just a little bending, something may be grounding out there or elsewhere, might be time to trace some wires.

 

[89Suburban]

The thing that don;t make sense is it has 12 volts on the wire, you figure if it was shorted somewhere it would keep blowing the fuse. It only blew when I grounded it.

 

[Jims86]

The thing that don;t make sense is it has 12 volts on the wire, you figure if it was shorted somewhere it would keep blowing the fuse. It only blew when I grounded it.

Hey John, I remember you saying that your check engine light is always on. can you stuck your head under the truck,and look at the transfer case tail housing, and tell me if you just see the cable(looks like cb antenna coax) or is it an electrical plug. Ifnyour Vehicle speep sensor is not working, the ECM wont command lockup.

 

[89Suburban]

Hey John, I remember you saying that your check engine light is always on. can you stuck your head under the truck,and look at the transfer case tail housing, and tell me if you just see the cable(looks like cb antenna coax) or is it an electrical plug. Ifnyour Vehicle speep sensor is not working, the ECM wont command lockup.

It has the cable drive, and the speed sensor is on the back of the speedometer. I replaced that cable about 2 years ago is my guess. Needle still bounces around a little.

I tried to pull the codes using the blinking light method and it just shot out the standard 12 codes, so it did not tell me anything was wrong. But the light kept coming on and off on de-accell from highway speed. So I just pulled the bulb out because it was pissing me off, lol.

What else can I do to pull codes off this POS?

 

[Jims86]

It has the cable drive, and the speed sensor is on the back of the speedometer. I replaced that cable about 2 years ago is my guess. Needle still bounces around a little.

I tried to pull the codes using the blinking light method and it just shot out the standard 12 codes, so it did not tell me anything was wrong. But the light kept coming on and off on de-accell from highway speed. So I just pulled the bulb out because it was pissing me off, lol.

What else can I do to pull codes off this POS?

Ok, so the speedo just bounces every now and then? doesnt show constant speed?
If you have not disconnected the battery in a while, you may be able to get a code or 2. each code will flash 3 times, first code is always 12.