I am swapping a CA20E with a CA18ET. The problem I have run into is that the engine has the LG/B as shown in the diagram, but the car does not. I had thought about not connecting it, but did not know if that would cause more problems. I noticed in some newer wiring diagrams, the LG/B is not even shown. Is it somewhere I can't find????
Its been so long, I can't remember. I think they're enclosed in a small hermetically sealed box, much like the resistors. Something make me think they were under the passenger side seat. I can't remember if I I went to the junkyard and got them, or if I made some. I think I went to the junk yard and got them - as no value was given.
What I can tell you, it that a diode is more often then not, a one way valve for electronics. Meaning the current can go one way, but not the other.
Sorry I can be of more help right now. But I did swap to an et, and I did build/mod my harness, and I vaguely remember those.
Don't be discouraged.
I was looking at the Mid Year 86 and 87 FSM, neither has the diode box to the ecu. Was going to just not connect it.
I will be pulling the dash to see if it is in that area. At this point I am thinking that on the newer models there was a design change. I will find out soon...
ha I just checked in my fsm, the diode box is on the driver side, just foward of the door. It's part of the main harness, not the dash harness, which is why I didn't notice it. I can take a picture of it if you want?
the connector is 71M if you have access to an FSM.
It has a diode for:
heater unit
power steering pump switch
illumination control relay
lighting switch (headlamp retract up)
door switch
time control unit
My guess is that you don't need it to get the engine running since none of these thing affect the engine in any way.
Update, finally got this sorted out. I ended up splicing my relays from the 86 into the 86.5, took weeks to sort out. Good news the ECU and everything else powered up like it should. And my question about the diode is answered and confirms below that it is not need to run.
My guess is that you don't need it to get the engine running since none of these thing affect the engine in any way.