need a wire wizard

have a wire problem involving the harness from cpu to engine compartment. kind of long story to be thorough so please bare with me

picked up 88 le manual hi low a few years ago, body is immaculate, undercarriage doesnt look like its seen dirt ever. 156000 miles, the one

problem was that rats had gotten in to van and ate most of wires behind the airfilter compartment and engining for the guy gave it to me for 300

and i had a van already so i got it. apparently the 88 le 4wd CA is rare or rarer i guess. after two years of religiously searchng for a van to

to match this one and talking to mechanics and toyota i decided that i had to just break down and rebuild wire harness. i worked in car audio

when i was a kid and then high voltage in seattle for a few years, now do alot of sidework on residential, point being i have a decent

understanding of electronics.

So the first dilemma is starting with the toyota factory electrical wiring diagram there is one generic set of schematics that doesnt

differentiate between CA and FED or Manual and Auto, no the later doesnt matter much but i think overdrive runs through cpu.

so secondly after going through about half the wire its seemed that everything matched accept for a few wires that were extra on

the CA car (had a federal doner harness) so i began to wonder if what toyota had told me (that no other harness could even be altered to work)
was true, and i have been working on other elements of the rebuild since. i have since aquired and 87 same except federal, and 88 same

except auto tran and push button and 86 parts van.


so sorry about the boring story but my main questions are:

1. Is it really impossible to frankenstein a wire harness to work?
on matching year harnesses i only saw 4 extra wires on ca model and assume they were for emissions wire layout seemed almost identical.

2. which is the best of these options?

a. remove cpu and harness from federal van? and hope it can pass emissions

b. try and rewire harness from near matching van to work? (except its auto/auto)

c. put the engine from van missing harness 150000 miles into van with bad engine and 380000 miles on it?


if anyone has any input on this, greatly appreciated. main thing is getting one more van on the road by spring so i have two running strong the 3rd can wait till mid summer.
thanks steve

First off, I am no wire wizard and I have never stayed at a holiday inn.
That said - There is no such thing as impossible, given sufficient time and money.

I doubt that it is impossible to make the harness work.
Easiest way I can think to make it all come together would be to get a hold of an electrical wiring diagram book.
This is a separate publication from the factory manual and has lots more useful things in it.
While it does not specify individual models, they are one size fits all, so ALL the possible combinations are listed with little notes beside, things like (LE, Auto….)
I have one for my 88 but have no capability to scan and load and it isn't the sort of thing that would fit well on standard photo-copy paper,
besides, having the book in front of you would also make things easier as all the notes on what is what are in there, the fact pages have symbols that require the keys at the front to decipher (at least for those that are electrically challenged, like myself)

Best part though is at the back where they actually have pictures of the various harnesses with all the plugs labeled.
That should give you the info you need on what is what and you can make you mods from there.
Maybe there is a member closer that would have a manual you could either scan or borrow?
This is the best I can do with my limited technology.
No idea why they are upside down, they didn't start out that way???
Attachment 1205Attachment 1206Attachment 1207

BB

i do have the 1988 van electrical wiring diagram and asked at toyota dealership if there was 4wd specific and they said that was only one
it does show pages for ovedrive and 4wd as far as those controls, but the cpu or ecu diagram that shows pin layout is just one type. i am trying to look at your pictures to see if it is the same after the wire routing diagrams is wire schematics page 1-5 that are also foldouts, on first page section 3 it shows pin layout for this under efi, does yours have notes or multiple pics for different model.

thanks for your input
steve

Nope, my manual is just as explicit as your.

I figured that you went through the harness and only had a few wires you couldn't identify and thought that if you compared what you found to the harness routing diagrams, you might be able to identify the circuits via the plugs.

Hopefully Tim will chime in soon with some better insight.

What I do know about parts guys (being that I used to be one in a previous life) they only have part numbers in front of them and rarely can tell much more than what is listed. Only to say that they will have 2 different part numbers on the harnesses with no interchange info, so they will often make the assumption that there is no way to cross over different parts.
Whats more, many of them aren't particularly "hands on" types which only makes things like this worse.
Often times, the differences are small and many parts will work even though there is no interchange info available.
I also think that ALL harnesses (mains and subs) are NLA, so it's kind of a moot point as there are no new harnesses available for anything.

ya that is the case and why i held up on rebuilding chewed one, there were only a few wires that were just missing, as they were probly emissions stuff CA model. so back to square one and i think i can just use this new vans wire harness as it same year model and CA only has Auto trans, which i think should just be overdrive and cruise control but those would be extra and i could just omit. The production date on van is dec 87 so i dont think it could be 89 and code on passenger plate is 88, because 89 started with yr32 i believe.i know what you mean about parts guys ive called all around country for the last two years and couldnt even get some guys to check model number on cpu. and toyota ya they dont care cause they dont sell them any more so no need to help us.
thanks for your help
steve

Sorry, confusing my posts, deleted the stupid '89 comments.

I am lucky to have a great parts guy who always goes the extra mile, sometimes it takes awhile cause he is very busy, but he never drops the ball.
I shouldn't be so hard on them, it really isn't all their fault, in most cases, in order to look up a part, they have to start with a vin#.
In that case, it gets even harder to try to figure out where various differences may lie.
In the olden days, we used to have BOOKS to look up parts, it was very easy to look at similar components between different vehicles and ascertain if there was a possible unmentioned cross over between pieces.

I would have thought that the differences between Fed and Ca cars would have been more about programming in the ECU rather than actual component differences.

Cruise was an option on all vehicles, so I suspect the wiring for that stuff would be there on all harnesses, regardless.
The major differences, at least on the wiring diagram, seem to be manual vs auto, LE vs DLX

Personally I would rather try adapting a harness from a manual than an auto as it would simplify a couple of things.
Only because if things like the clutch start switch vs neutral safety switch.
Different wire colours and connectors, not to mention their physical locations.
The auto harness will also have all sorts of wires for things like trans oil temp, overdrive and possibly other stuff?

BB

ya those are great points. thank you. new parts van is getting delivered tomorrow, will know more this week, when i will have to different harnesses to compare ca auto fed manual. Then will probably just put computer and harness out of fed man into ca manual and try and make work.if cant then engine, ecu, and harness swap.
thanks steve