92DIESEL

I tried doing the pointameter thing that Ouachman put up. Well I still dont have OD. I need OD bad
I have some jiuce to the purple wire and hear a relay on top of the drivers fender click on and then off. I swapped out the relay and same thing.
When I turn the pointameter all the way to the right I get jiuce to the middle wire(orange). Am I supposed to? I check all the fuses and fusable links- there all good. I checked the coolant temp and distance sensor and seem to be fine. I have my speedo just no OD.

Sorry for the long post but I'm at my wits end, I've been trying everything since Thursday. I hope someone can help me.

Thanks in advance, I'll check back tonight.
Michael

JD730

I reccomend putting a switch in to control OD directly. This will allow you to do a couple of things, have OD, eliminate the OD selinoid in the trans and trouble shoot the rest of the system at your leisure.

Going to need some wire, a creeper and some light. Crawl underneath and find the 2 wire connector on the drivers side above and behind the shift levers. 1 wire will have 12v with the ignition on, the other wire goes to the PCM and with the inputs you meantion ealier determines when to shift into OD.

Take air and blow any dirt away from the connector before you unhook it, trust me, you don't want it falling in there.

Splice into the wire that goes to the PCM, should be alittle smaller than the other one. Run it into the cab and set the switch in a convient spot, connect the other side of the switch to a ground point. Providing the selinoid is good and it has 12v going to it you should have OD manually through the switch.

cLAYH

On my truck I used a floor mounted dimmer switch to activate OD manually. Just tap it with my left foot. Don't have to take my eyes off the road or hands off the wheel. I did install a light on the dash though to remind me when it was in OD. Kept pulling away from lights in OD.

ChrisLib

Don`t know if it`ll help but see here
https://www.dieseltruckresource.com/...threadid=72661
and my followup here
https://www.dieseltruckresource.com/...ighlight=fixed

FrdRdnk

Hey Michael,
Don't really have any advice but if ya need some help give me a call. I'm home in the evenings.

th_racer

you should have 7.5 volts to purple wire all the time, turn your new pot upside down,and hook the purple(to the right) and black(to the left) orange to middle,wires just like they are on the on the original, then set the volts on the orange wire to 1.6- 1.8 volts. remember to ground to the battery when checking all these . It works great, cruise works, od button works and you dont have to remember to turn it off. Terry , By the way, are you sure you got a linear pot and not an audio pot, the audio will not work right.

92DIESEL

WOW you guys are awsome, I can't thank you enough, I'm going to fix it in the morning. Pot first, if not, drop the pan & check solenoid, and if all else fails mystery switch.
I have half the truck rigged already, what's one more switch - At least I can say no if someone wants to borrow it right




Yes I got the Linear. I have to find my meter to get the volts coming off the pot.

Sam- If you want you can stop by anytime, I'm in between jobs right now

I'll let everone know how I made out in the afternoon.

Thanks again,
Michael

ouchman

Thanks for helping me explain it - sometimes I have a hard time putting it in terms that people understand. I also feel bad when someone tries it and it doesn't work for them right away. I know how cool it is when it works!

92DIESEL

Well, I didn't get a chance to work on it today. I hope I'll be able to get to it in the morning. I think I'm going to just do the switch for now since I'm not having any luck with the pot. I don't have a multi meter handy so I can't figure it out right now.

Just wanted to give an update and thank everyone again,
Michael

92DIESEL

sorry for being such a PITA. I tried doing a mystery switch today and I don't have any juice down at the transmission. I then looked in me FSM and checked the OD switch. I have power to the #6 location but nowhere else. When I press the switch it lights up but thats it, no power coming out.
Does this mean the switch is bad and if so how can I wire in another switch for the time being.

Sorry for the long post but I just don't understand electrical

Thanks again guys, your the best.
Michael

apwatson50

If neither wire at the transmission has power than you have a blown fuse or fusible link somewhere. I don't remember which wire but one should have power all the time. Then when you want to engage O/D you ground the other wire and that completes the circuit.

92DIESEL

Thanks but I've checked all of the fuses and fusable liks(I think anyway- there all over the divers side wheelwell right?)
From what I'm seeing in the FSM I should have power coming out of the OD lockout switch- I don't
I think I'm going to have to find a new OD lockout switch and see if that works, as of now I'm stumped.

Thanks for all your help,
Michael

wannadiesel

The OD lockout switch just tells the PCM what you want. It is in no way connected to the OD solenoid, it goes straight to the PCM. Don't worry about the factory switch when you are trying to wire your mystery switch.

You should have power on the dark blue wire down at the trans. Ground the orange wire and you will have OD. If there's no power to the dark blue wire, just run another one off the ignition feed - that's where it comes from anyhow.

ChrisLib

I only have a 1990 FSM (got it fro free ) but from what I can see, the OD switch does not directly control the OD solenoid, it simply send an on/off command signal to the SBEC. If you don`t have 12v at the solenoid you could have a bad link (wich you ck`ed) but if the link was bad you would also have a bunch of other stuff not working. Could be an open circiut at splice J2 or the harness connector on the engine (the black one about 2/3 way back on drivers side) I would start at that connector and ck for 12v there, on my truck i found a good amount of crud/corossion in that connector. If you can, put up a pic of the wiring diag for your year truck (my book the OD ckt is on pages 8w-54 and 8w55).

92DIESEL

Thanks again to everyone. I am going to just run a new 12v line off the ignition and have a switch for now. I am starting a new job on Tuesday and am going away Thursday till Monday morning. so I don't have that much time to play with it anymore.

Thanks again all,
Michael