Ok turbo96max here we go, lets start from scratch.Bison was right about the ecm controlling the l/u sol. on the ground side. and according to that schematic there are two pressure switches on a brf valve body or whatever that schematic is for, not even sure that's for a brf tranny.now the problem that I have is I think the schematic is wrong or not for this car,i have been in this industry for a long time and believe you me Ive seen plenty of things wrong on schematics. I happen to have a brf torn down in my shop as we speek and guess what, only one pressure switch and its normally OPEN. I looked at my schematics and I have all of them for everyone of the other 200s for the other cars but cant seem to find one for this particular tranny and it shows them to be n.o also but either way, that is all a moot point anyway and heres why. you don't need to know if they are a n.o switch or n.c switch, just whether or not its sending a signal to the ecm saying hey im in third gear ,or forth gear ,however yours is set up, so it can energize the l/up sol., and quit exhausting fluid into the pan and allow the lock up valve in pump to be stroked, and apply the clutch. Now that weve cut through some of the garbage, lets start diagnosing. If this car came in to my shop this is how and where I would start. turboburick was right first place to start is to make sure we have 12 volts down to trans on red wire cavity a,thats 12 volts with a meter not I have juice with a test light.Now if we don't have 12 volts down to trans we need to do a voltage drop test, in other words we need to start looking to see where we lost our voltage and start backtracking that circuit backwards towards the voltage source until we find it. First place I would look is the easiest place to acces, fuse or brake switch,once we find where we lost it fix the problem and youre back on the road again.Now if we have voltage down to trans. then obviously that isn't it and we need to go further in our diag. Ok so our next step will be control side, which in this case is the ground side of the circuit the ecm. Now this is how I would personally go about this, the f pin on the aldl connector is on the ground side of the l/up sol. so lets look at this scenario, say you ground this sol. through the aldl connector and wallah it clicks 15 times, you say well it must the computer not supplying a ground, but how do you climb into the computer and see if its doing its job or not, grounding the circuit. This is where a lot of technicians start throwing parts at it. Me, I want to know if its in the computer before I stick my neck out on the line and tell the customer you need a computer for x amount of dollars, and cross my fingers that it fixes it, knowing full well Im not 100% sure.So on to more diagnostics, hang with me almost there. Remember the reason I personally don't like checking the ground side of the circuit from the aldl it leaves out the rest of the wiring in the ground circuit, the connector to the ecm, and the ecm.So now what,we need to see if the wiring is good between the trans connector and computer, black wire ,terminal d. Ok now, there are several ways to do this and how most people are taught is the ohms test which I don't care for and ill tell you why, automotive wiring is made in strands and not solid like house wiring, if I cut 6 of the seven strands of wire and ohm it , guess what, it will test good , but it will not I repeat will not carry a load. Now to test it get a wire from youre local parts store with a fuse holder, and use a fuse, now jumper that wire to ground unplug the connector from ecm,and find socket from the trans ground wire. now on this end youll need a headlight bulb from a new car and jumper it over to battery pos. if it lights up nice and bright you've just determined that that circuit is good and can carry a load. now disconnect yourelight bulb and youre jumper and plug in the connector down at trans. and leave ecm connector unplugged, turn key on engine off, ground ecm wire to battery see if sol. clicks if it does its either computer driver in ecm ,or its the pressure switch not sending signal to ecm. to ground l/up sol.If this doesn't lead you to the fix let me know and ill tell you how to trouble shoot pressure switch, its the last thing left. I apologize to every one out there for such a long post I just know that this plagues a lot of people,so my apologies.Bye the way sometimes the sol. check ball after it gets energized once will stick and you wont here it click again you have to pull the sol. out and apply a little air pressure to the snout down bye the o ring.
