EEC Fuse and the MLP Sensor

[Glacier991]

Ok connector diagrams. Here is the main case connector, note the orientation of the ears on it and the pin numbering...

Here is a harness view... in 2 pictures.... left half:

Notice that there are 2 solenoids with a wire to pin 10. That is SS (shift solenoid) power. They all share a common power supply. The PCM just provides a ground to activate them.


right half, note they have a 10 connection, the bottom one, 7-10, is the SSC

and here is the legend. The portion lost to the flash reflection says "Shift Solenoid Power" for 10

Ain't ya glad you came to THIS board ? <g>

If ya ain't in a hurry.... try this

http://cgi.ebay.com/ebaymotors/New-...999999034QQcategoryZ33727QQrdZ1QQcmdZViewItem

Seriously, good luck, let us know what you find. If it is the SSC you owe me a beer someday ! Oh and.. I should add, the dealer suggesting the TR sensor was on the right track, just wrong place.

 

[paul.milne]

That's great! I'm not sure about what's ahead of me but I'm sure it will be a challenge.

I'm definitely sold on this forum... I've been advertising it for the last two years to my friends. Most of my problems have actually been solved by searching the text. This is the first time I have had to have a dialog to get to the bottom of a serious problem. There is no doubt in my mind that this forum is one of the best things going for explorer owners... I'll keep spreading the word whenever I meet an fellow owner. I especially appreciate your help, thanks so much.... I think I owe you more than a beer but we'll address that when the vehicle is back on the road... I'll keep you updated. Thanks again,
paul

 

[paul.milne]

Ok, I have a problem. Using an ohm meter I measured the resistance between just about everything. Here are the results:

Resistance between Pins in Ohms:

10- 7: 26.5
10-16: 26.6
10-14: 26.5
10- 9: 26.9
1- 5: 9.8
11-12: 3.7
4- 8: 33.73k
2- 3: 73.7


Resistance between the transmission case and the wiring harness:
1. 629k
2. Inf
3. 0.7
4. 18.58k
5. 102.7k
6. No connect
7. 102.8k
8. 0.4
9. 103.1k
10. 629k
11. 629k
12. 6.85k
13. No connect
14. 102.9k
15. No connect
16. 103k

As far as I can see the results are good. The solenoid resistance seems to be the same for the four solenoids that share connection 10. Also, all the readouts that I would expect to be similar are similar. I don't think I'm finding a problem. Do you see anything? What do I do next?

 

[paul.milne]

I tried another test. I left the wiring harness disconnected and turned on the car. I shifted through all the gears and no problem, even in 2nd gear. Now without the harness connected I'm not sure what the transmission does when I put the lever in the 2nd gear position. Does this tell us anymore information? It seems to me that this directs me back to a problem in the wiring harness. I also keep the ohm meter on pins 7 and 10 and the resistance stayed constant throught the test.

 

[Glacier991]

For the cost, I think I'd replace the wiring harness. I'm not where I can reference the manual, but I can tell you that the resistance for your solenoids is ok. I'm thinking we should have seen more infinite resistances in the harness. I'm suspicious of the harness. But then I was almost certain you were going to find a bad SSC solenoid too.... soo, what do I know?

If this doesn't get it, the next steps need a breakout box and a transmission tester.

 

[paul.milne]

How do I go about replacing the harness? Does it just connect in at the other end and I just swap it out? Or is it more comlpex than that?

 

[paul.milne]

I forgot to say, I get infinite resistance when I have the car turned on for the solenoid pins in the wiring harness.

 

[Glacier991]

I am referring to the wiring harness IN the transmission now..... It's pretty intuitive, but yer gonna have to drop the pan. On the off chance, while yer in there I'd swap the solenoids on the 2 solenoid side.... one for the other. AND replace the harness.

(This would have the effect of "possibly" moving the problem pinpointing the old SCC solenoid as possibly intermittently bad if your problem repeated in another gear.)

Just a thought.

 

[Glacier991]

while yer in there, double check that none of the pins on the solenoids are shorted to the case ground.

 

[paul.milne]

I did that too. In fact I checked the resistance between every pin on the transmission and the transmission case. All came out as infinite resistance.

 

[paul.milne]

The swapping solenoids is an interesting thought. Btw, why do you think it has to do with the wiring harness inside the transmission and not from the engine down to the transmission? Is it because I didn't find any shorts while testing the leads?

 

[paul.milne]

I called the ford dealer about the inside wiring harness they said all they had was part number E7SZ7E449A. But the guy didn't seem very confident that that is what I wanted. Any idea if that is the right part?

 

[paul.milne]

I took the plunge and dropped the pan... what a mess. I also called a local transmission shop and spoke to a guy who said he thought it was the solenoid. He didn't seem to care that the ohms were in the correct range. But he also said he thought it was the 1-2 shift solenoid which he said was the B solenoid. To be sure, he said to disconnect the wires at the solenoid and shift into 2nd. I said "With the pan off?" He said yes. I am still skeptical that this is a wise move.

Can I really run the engine and shift the transmission with the pan off and half the fluid missing?

Also I am unsure how the connectors on the solenoids come off. I tugged down on them a little but they didn't want to seem to come off that way. I then pulled to the side sort of straight off the top. That didn't seem to work either. I'm afraid I'm going to break the little plastic pieces; how do these come off?

 

[Glacier991]

He wasn't suggesting you run it with the pan off, just shift into that gear. (I sure as heck hope anyway - in other words DO NOT RUN IT WITH THE PAN OFF!!).

The A solenoid is on the same side as the C... it is on in 2nd, but it is also on in 1st, which made me think earlier that it couldn't be the problem or you'd short out in 1st.


The generic part number for the harness is 7Z409.

If the shorting was occurring in the harness to the main wiring and pcm, it would have shorted when you were try shifting with the connector to the trans undone I would think. The solenoid connectors are just male spade lugs. Try needlenose pliers to pull the connectors off. They just slide off.

I am perplexed. Everything is screaming SSC solenoid. If it ain't that, it practically has to be the harness. The other thing to remember is that there is always 12V present at the solenoid..... the gets actuated when the PCM gives it a ground. Maybe the solenoid internally does something that causes the short. I can send you a replacement solenoid to try if you want.... but changing the position of SSA and SSC and then trying your experiments would do the same thing, diagnostic wise.

I'm feeling frustrated at not being more help.

 

[paul.milne]

Thanks so much. I'm sorry for your frustration, didn't mean to share mine with you... But maybe things are looking up! I think I found the problem not more than a few minutes ago, plus the time it took me to wipe the transmission fluid off my hands and arms.

I couldn't see it at first but I started poking at the wires and found this: This is a picture of the left side of the transmission with the pan off:

Here is a close up of the second solenoid back; I'm not sure which one this is.

The wires looked melted together, and when I pulled them appart they certainly look like it. Besides the missing casing on the wires, note the nice orange bubble in the bottom white wire.

Now... you got me this far, what do I do? Can I simply fix these wires like normal by cutting them, stripping them and adding a connector... OR is the only way to fix this, to replace the wiring to all the solenoids with the harness you suggested? And is does the harness you mentioned actually have all these wires and connectors? Or is this a different set? Also, I am wondering if the short has caused any problems with the solenoid itself; maybe it is wise to replace anyway?

 

[Glacier991]

I'd say it is doubtful the solenoid suffered any damage. And yes if it were me, I'd replace the entire harness. Looks like you found your problem.... and I am NOT going crazy after all. Thanks for sharing!

Also, let's assume a new harness solves your problem (I believe it will) let's then dissect the old one and see if we can reconstruct the failure mode. I am still struggling with that.

Inquiring minds want to know.

 

[Glacier991]

I just noticed. I think this may set the record for the longest thread that was mainly a discussion between only 2 people. (I hope we were at least interesting!)

 

[paul.milne]

I think I'll print out the picture and the part number you gave me and bring it with me to the ford dealer tomorrow and see if they can get the harness. I sure do appreciate all the help; hope this works! I'll update the thread when I get it put back together (if I don't run into any more problems along the way)

Thanks again

 

[paul.milne]

I kept wondering if anyone else was going to chime in... guess not

 

[Glacier991]

My comment was not meant as a slam on anyone. This was a difficult problem, and one where having the factory transmission manual made all the difference. I'm gonna guess not a lot of us have that benefit. luckily I do, and was happy to share what i could.