rawfeels

(mods...i had posted this in the general section by mistake. please delete the other posting)

truck is a 1991 3.0 5spd 4x4

a few days ago my truck started smoking out of the a/c vents. i took off the cluster to see if the smoke was coming from in there. I couldnt figure it out and im crappy at wiring.

so i took it to the shop and today they told me there were a few wires that were melted together from something the PO mustve put in there (an alarm or stereo). Anyway they said they could check for more burnt wires from the gauge cluster all around but suggested i get a new harness to avoid blowing up the fusible link etc. they wanted like $500 including labor to do it. im mostly poor. well...poor enough that this will have to wait a few weeks.

would it be easier to go to the yard and find a harness there? is there a certain type i need? (if the harness is from an automatic would that still work?) the dealer told me the harness connects behind the firewall. does that mean i need to remove the engine to remove it?!

i dont know what im looking at really. but...if its going to be sitting there, i may as well start learning right?

Co_94_PU

iTrader: (-1)

behind the firewall = back side of the firewall = inside the cab behind the upper dash.

That is posssibly to rebuild the harness, pretty sure OEM harnesses are as rare as hens teeth.

For a plug and play install you'll need to match all the variables, Manufacturing plant, 4wd vs 2wd, Engine, Transmission, Model trim, and emissions type.

Now of course if your determined and creative enough you can make any of em work, it just won't be plug and play.

rawfeels

i found a harness from a 3.0 4x4 5spd with power windows just like mine from a dismantler for $150. it looks to be in better shape than mine...at least its missing the 4" burned section coming out of the kick panel fuse box.

so im in the middle of taking out the dash and all that so i can see what im doing and labeling the wires as i go along. i got stuck the other day with the big support bar thing. its blocking the harness from coming out easily near the steering wheel but i cant tell what bolts are holding it in aside from the 4 on either end of the connection (on the left and right side of the truck). it looks like its attached to the steering column.

hopefully once i get this bar out and i can see whats what...this job wont be such a pain. and hoipefully the plugging everything back up is less of a hassle than taking it all apart. Heres to hoping!

Co_94_PU

iTrader: (-1)

There are one or two bolts at the right hand side of the of the insturment cluster indent. And atleast one over the heater controls center area, and maybe another near the glove box. Some of these you have to attack from the upper rear, I remeber them because of the worry of smacking the windshield, and maybe some knuckle busters you need to attack from the bottom.

Keep at it you'll get it

rawfeels

updates.

ok so i replaced the melted wire. it turned out to be a wire that connects from the p/s kickpanel, breaks off into like 4 places, and leads to the fuse box under the d/s kickpanel. it was a black wire with a brown (gold?) stripe.

this is kinda what it the whole circuit looks like (though so far ive only dealt with the p/s kick panel forward because i thought the issue was only the under dash harness)


battery --->Main fuse box in the engine bay----->p/s kick panel plug ----->1-2 various nonsense plugs in dash-----> fuel pump relay in dash----> a couple more nonsense plugs in dash----> gauge cluster ----> d/s fuse box plug



so i cut out the old melted wire and looked at all the places where it had stuck to other wires when melting. Nothing else seemed messed up. I replaced the melted wire but left all the splices from the factory mostly in tact ( a couple i replaced with butt connectors). when i was done replacing the wire i went to hook it back up and see if the harness works. I checked to see if i had continuity from the d/s end to the p/s end and my little meter showed something small, i forget the number. But i did compare it to an untouched wire and the number was basically the same. this was done inside my apartment with no power source. just testing the ends of the pin connection from d/s to p/s side.

anyway when i hooked it back up and turned on the key, i couldnt hear the fuel pump turn on. thats one problem thats not so big just yet. But the big problem is that smoke started coming from the p/s area where the connection was. i turned it off so it wouldnt melt again. the wires felt hot to the touch.

my question is...if the wires are getting hot and the only thing that comes before the p/s kickpanel plug is the main fuse box plug in the fusible link, what is making this heat? i just found this part out last night so i havent taken the fusible link apart yet to see wtf is going on in there. but like...its basically like the wires are getting too much power to them and theres something missing in the fusible link to stop it from transferring so much energy through it. does this mean a fuse in the link is broken or something? (i'm going to check the cabling from the p/s plug to the link when i get a chance to make sure its not melted too)



edit: truck is a stock 3.0 4runner 5spd 4x4 if any of you dudes have the wiring schematic for this thing. the FSM doesnt really show much as far as what connects to what. but the wire was a black wire with a gold (brown?) stripe

rawfeels

another thing i just remembered...

i shouldve taken a picture but..in the main fuse box i couldve sworn i had two grey cylindrical fuse things inside along with the other fuses. now i only have 1. also...there are a few fuses lying around on the floor next to the fuse box under the driver kick panel. i compared it to the extra harness/fuse box i have and it seemed ok. but is there a picture somewhere that shows what is supposed to be in there?

i have the fsm but the junction blocks are always different. i dont know if its because my truck is a 91 4runner and not a 93 pickup. the starter relay for example in the fsm is supposed ot be under the dash. its actually on the fuse box in the drivers kick panel.

Co_94_PU

iTrader: (-1)

The primary fusible link is rated for more than the primary fuse, eg more than 80 amps, I don't know it's rating off hand.

It may of been me that told you "it's to keep the harness from busting into flames", let me clear that up a bit more. The main fusible link is designed to keep the battery from off gasing and to prevent a hydrogen fueled fire.

Links are here

don't hook it up till you find what is shorted out, it'll just melt again or melt something/where else

Well my first question is are you color blind ? I know it's kinda of a PITA some times. Not seeing any Black with gold or brown, there are some Black and Yellow.

Can you identify where those plugs/splices run to in the first picture I'm attaching? It'll help tracking down what wiring is involved.

The second picture contains the fuel pump, were you refering to the Circuit opening relay?

Do you have cruise control?

You can disconnect the battery and the plug to the gas tank/fuel-pump, then test for a ground short at the diagnostic port should be relativly quick. If you have ground on the FP pin at the DLC with the pump disconnected it's maybe in that relay. Pull the relay and check both sides to isolate it to one or the other, if niether show a connection to ground it's internal to the relay.

rawfeels

the wire connectc ont he back of the fuse box. in your first attachment it connects in between C5 and H8 (looks like I16, but the picture is a little blurry). anyway it connects there. if memory serves me correctly its the 3rd or 4th pin from the bottom. it then goes along the top to (i want to say C8) in the cluster, a few other places, and ultimately (maybe) D13 where the connection is just a male connector that connects into the engine bay. The opposite sidecontinues into the engine bay to the main fuse box.

also, im 100% positive that it connects to the fuel pump relay because it says "fuel pump relay" on the box. its just behind the dash cluster hanging around there as if it has been taken off before. The circuit opening relay is in the p/s side kick panel. in your attachment it looks like G4.

here is a picture of the coloring. looks like black/orange under a flash

Co_94_PU

iTrader: (-1)

Gonna say that is a black-yellow wire.

Here is the direct link for your FSM + Wireing

That first picture is from,
Toyota.4Runner.1990.1995.SIL\FSM\ileaf\toyewdvf\to yewpdf\vfewdsou\1995\954runne\electric\componen.pd f , 5th page #28. It will help you ID those connectors.

Toyota.4Runner.1990.1995.SIL\FSM\ileaf\toyewdvf\to yewpdf\vfewdsou\1995\954runne\powersou\pwersourc.p df, 1st page lower right. The wire at Ig1. I think this is the wire you're working with. It carries alot of current, supplies those 4 fuses in the picture.

If you look at the overall diagrams(overalle\overalle.pdf) 4th page, at the bottom of the page, notice that is feeding 70amps of fuses in the kick panel thru a 40amp fuse.

Not sure what guage wire is stock or what you replaced it with. This wiring chart, gives info on wire size and carrying limits. it should be somewhere inthe 12-5AWG range, that is probably 16g just guessing.

Now onto figuring out what is actually shorted out, You will need an amp guage(ammeter/multimeter) preferably with a high rating(20+ amp) and clamp type.

Disconnect those four fuses, engine, wiper, turn, and guage, in the left hand kick panel.
Disconnect the ECU-ig fuse, in LH kick panel.
Connect your meter where the 40a fuse is in the engine bay, or around it's wire if clamp type.
Make sure all the accesories are switched off.
Turn the key to the on position momentarily, and verify there is little to no current flowing.

If you have current flow with the fuses pulled there is a short in the wire somewhere, verify none of the fuse box connections are burnt up or otherwise conducting. Disconnect the 40A fuse and probe for for a short to ground. (establish a body ground and start probing. 40a fuse oppossite side of the battery, eg non powered side we just isolated. Then each of the fuse junctions in the kick panel, again the side we just isolated). The place with the lowest resistance(Ohms reading) is closest to the short. Inspect, test, and then replace anything that is chared or damaged.

Now you have clean verified wire to the kickpanel from the engine bay. We need to verify there are no shorts in those five fuses. Replace the 40a fuse with a 10 or 20a fast blow fuse this is to protect the wiring and meter. Verify all accesories turned off. Place your meter in each fuse recepticle one at a time and verfiy there is little or no current flowing when you turn the key to On.

I did not trace out all the wiring on those fuses, but I expect there will be current on Engine and Ignition. these are ok as long as they aren't excessive, eg more than thier fuse rating (or maybe 50% of the rating).

My guess for causes would be shorted out light bulbs in either the guage cluster or turn signals, the wiper switch or relay may have issues aswell..

rawfeels

man...i understand why people hate electrical

ive stared at these files in the fsm and am making some progress in understanding them, but its still a bit fuzzy.

so far, ive traced the majority of the wire connections. they are... (in order of connection from drivers side fuse box to passenger side end point (the connection that leads into the engine bay).. the end numbers are the ohm reading that i found. ohms were found by connecting one lead to the integration plug end and moving along each connection in order. in other words, from the integration plug to x (this is why integration plug has no reading)..

I16-integration relay
D11/D12?- door control switch or door control relay (its a blue box about 5"x4")-22
A18-auto antenna control-14.9
C11-combination meter (seatbelt warning light?)-3
C11-combination meter (back door light? cruise control light?)-.5
Fuel pump relay (still cant find this in the diagrams)-top left-.6
-bottom right-.6
another antenna possibly (cant find in diagrams)-3.3
C7-Circuit opening relay- top left relay-.5
top right relay-.5
End-.5 (this is why i said the other day the connection from end to end was low)

now...im no expert obviously but it makes sense that the farther away from the origin reading (the intergration plug), the more resistance (probably not much because the whole harness is maybe 6'). But those readings of 22 and 14.9 really stick out relative to the other small readings of .5-3.

so its seems your guess about burnt out light bulbs in the gauge seems plausible. especially because this truck has known odometer fraud issues (they replaced the cluster)

most of these connections were found using the first attachment you had put up and the overall wiring diagram. i then searched the pdf (ctrl-f) B-O. it is a black with orange stripe. the problem is there is a TON of connections and im still trying to learn how to read this thing. but...its progress.

thanks for the help so far!

Co_94_PU

iTrader: (-1)

There are tests you can run on most/all of these relays and switchs and other various do-dads. Look thru the FSM for them and check them out, it's easy stuff. You'll be a wiz with that meter before long

B-O integration relay pin #9, usbw.pdf has a picture of the plug. Supplies lots of stuff for sure.

This is all on the guage fuse. There are a few things that would backfeed power (ecu,ect,cc-ecu, maybe some others I'm forgetting) thru the lightbulbs so those would need removed but you could I think run without the guage fuse. If you dont get heat or smoke w/o that fuse atleast it's better isolated to the one circuit section.

The .5 ohm reading is correct for ~50ft of 20guage(7 strands of .20-.26mm, from memory) I don't expect that is that much there. Need to identify that wire guage. 0.5 Ohm over an 8' run is around 28g wire.

These Ohm readings are with the plugs you've identified disconnected, So you're seeing just the wire resistence between point A to B and not any of the attached circuits, correct? Those readings indicate there is still bad wire or there is something attached altering the readings.

I assume you have the plugs connected still.

Do the short to ground tests. Label both sides of the connectors you've identified, and/or take pictures so you can put them back. With the identified plugs/devices unpluged and the guage fuse removed. Attach meter to the ground in the kick panel and check resistance at each of the removed plugs. If you have conductuvuty there is either something still attached, or a short to ground. The place with the lowest resistence will likely be nearest the short or connected device. Not It might not be physicaly the closest but electricly, so for example the wire runs back to the relay box and splices off.

Hopefully you find no conductivity in the ground short tests. This means it's just a bad device or too and maybe some charred/heat-damaged wires still.

The splice point map is in the electric\connecto.pdf. You could visually inspect in those areas for shorts, exposed wires, chaffing and other gremlins.


I'm feeling a little obligated to point out the time spent on this issue. 150$/minimum-wage You're probably there already. But if you want to keep at it and trying to pickup wiring debugging I'll keep trying to teach it

rawfeels

yeah at the moment, i dont have the cash to pay somebody to do this. the plan was to try and figure this out myself while waiting for my tax return to come in. and if i do, great. if not, at least i half learned about something. the added benefit being that the harness and dash etc will be torn apart already...so the end bill wont be as much as labor time should be decreased haha

in any case, those Ohm readings were taken with everything plugged in that had a wire necessary for the truck to start. thinking about it now...yeah thats probably pretty dumb. So today i will do it 3x and see if i can see any difference.

first time, i will just unplug everything from the entire harness and test the b-o connections unplugged from the circuit. second time,ill try this short to ground test and the third time i will plug in only the b-o connections and test individually (unplug each connection as i move along).

thanks again. hopefully this thread will help someone down the line.

Co_94_PU

iTrader: (-1)

Don't do the third test you mentioned, do the individual part tests from the various sections of the FSM. There aren't any references for "that" test method, so it's just wasted time.

If you do wind up sourceing a new harness you should be able to install it yourself with your new found affinity to the dash area. Free labor is cheap labor