1985 4 banger wiring and under the hood pictures

I am trying to track down a battery drain on my 85 4 banger right now. There is standard Bosch square relay near the battery (left one of three) that comes on when one red wire is connected to the battery and the ignition switch is off (the red wire comes out of a large fat harness near the battery). It turns on one of the electric vacuum valves on the driver's side. Pulling the Bosch relay turns both off. I suspect a shorted wire somewhere, possibly a shorted to ground switched ground wire (as a grounded hot wire would blow a fuse and or melt the wire), that I need to find.

I think the red wire also powers the radio (need to verify this) as I am told it was lit up with the ignition switch off (but some of the wiring is custom under the dash), so I need to check that. This is my diesel converted jeep, SD-22 Nissan. 75% of the old vacuum lines and wiring under the hood is bypassed, no longer used, but this new issue after 10 years needs to be located. I will be trying to find out if anything else runs on that red wire that I need. I could use photos or images of the 1985, 4 banger under the hood parts layout. I have a Haynes so I have some wiring diagrams but posting up one that shows me what this wire powers would help. I suspect it is a hot all the time wire. I see no fuse link on it either.

I have some of the early jeep electrical books which has some wiring detail but I'm not going to be home before Wednesday.


Sent from my iPhone using Tapatalk

If you have a DMM with milliamps you can do a current drain test and start yanking fuses till current drops and that will tell you what is doing it

xCWolf said:

If you have a DMM with milliamps you can do a current drain test and start yanking fuses till current drops and that will tell you what is doing it

Click to expand...

Milliamps might not cut it. It completely drained a fully charged 1000 amp hour new battery to 0.5 volts in about 24 hours. I have killed 2 of the loads, the relay and the vacuum solenoid valve running off that relay, but there is still a load active enough to spark when I touch the + post with the power wire. Will post pictures later of them. I may be able to just abandon that wire if it operates nothing I use any more. The starter wires are separate, and the headlights are on other wires. Still need to test the AC clutch, tail lights and brake lights. AC blower has new independent wiring. I think that is all I need for the diesel rig as the engine just needs power for the glow plugs (also on a new circuit), and the starter circuit which I already verified is not on that circuit.

But I am curious where the short came from and what all is on it. Like maybe the radio since I am told it was lit up before I pulled the bad power wire.....Radio could be easy to reroute.

Edit: In other words the load is/was large enough to spark in daylight so far. But a DMM will not tell me where the short is

But pulling fuses at this stage is a good idea, if the load was under 5 amps on a 5-25 amp fuse.

I can see why that would be an issue, but if you have a DMM that measures amps you could do the same thing. or a hall effect clamp if you think its OVER 10 amps.

xCWolf said:

I can see why that would be an issue, but if you have a DMM that measures amps you could do the same thing. or a hall effect clamp if you think its OVER 10 amps.

Click to expand...

This is true.

But at my age, and illness (Rheumatoid Arthritis from hell), an extra walk across the property to dig out the meter is painful when a spark test is still working LOL. With this escapade while I was unlucky enough to develop a short, I was lucky enough that it sparks and was supper easy to find

I have a stash of lone DC amp panel meters and DMMs, one goes to 10 amps (DMM), and other panel meters go a lot higher. I use to service DC power supplies at plating shops in another life.:eyes:

What I need here, and now is the wiring and emissions crap layouts on the 2.5 L, 1985 OEM beast so I can determine what the name on that relay was. I am guessing an EGR solenoid, or similar, possibly an O2 sensor heater relay....but it seems to be powering more than one thing. I will check and photograph the fire wall sticker tomorrow if the rain lets me.

I should be able to pull it up tomorrow at work and I can prolly PM you a (bad) pic of the wiring diags and what the relays do

Here is some wiring from the 84 electrical book



Sent from my iPhone using Tapatalk

Here is the 1986 i4 wiring




Sent from my iPhone using Tapatalk

Power distribution 1986




Sent from my iPhone using Tapatalk

Well crap it rotated the pictures .

Let me know if there are any that are too out of focus


Sent from my iPhone using Tapatalk

I have isolated it to the head light switch and its wiring, which by passes the ignition switch on my 85. BTW, my sticker lists it as a ZJ, not an XJ. Is that the motor size?

Still trying to determine if this 85 gas 2.5 had a computer, and if it was TBI or carburetor.

Didn't they make both in 1985?

My emissions sticker on the firewall looks like it says it was a Carb? I will try to post the photo link.

Yep, it clearly uses the word CARB on the throttle body area of the map and connected parts, so mine had a carburetor, no O2 sensor, it was not TBI, no computer so the wiring on mine is a base BASE model, no electric windows, locks or fancy stuff at all. It is a Cherokee Pioneer, Bare minimum of stuff, 2WD only, no transfer case....

I found some wiring pages here

http://oljeep.com/gw/elec/cherokee/edge_cherokee.html

But none show photos under the hood pointing out what each of about 30 odd parts are under the hood, still hoked to old vac lines and wiring (solenoids ad-infinitum) for all the old emissions crap.

Mine is custom, Nissan diesel swap for the old gas engine...Manual Transmission.

Like I said I have isolated the remaining problem to the running lights wiring (when I disconnect that wire at the battery I loose running lights). But with it connected I have no running lights with the head light switch off, but they work with the HL switch on, for head lights or just running lights. Also the shorted load is less with the HL switch on, than with it all the way off?

Could the head light switch be shorted out in the off possition internally? I have never seen or heard of this, but maybe others have???

Mike, I found that manual for you and will see if I can get it in the mail to you. It is in pretty rough condition, I used it for a back stop drilling some small holes.

That year did in fact have a Carter YFA carb. It sucked. It actually had a computer controlled jet. The biggest failure mode was the electric choke. The ground contacts would corrode and the choke would not heat up causing it to open, so you ran way too rich all the time.

I got pissed on mine and ripped the carb off and hit the junk yard for the throttle body injection and computer. It made a world of difference in the power and just how well it ran.

Old Man, Thanks!!!

BTW, I hear all carburetors suck, LOL.

All I can say is thank God they switched to MPI computer rigs as that mess of vacuum hoses and valves was nightmare on elm street for sure.

I escaped that saga and jumped from 1978 to to 1987 and thank God I missed all the fun in between. My 85 was already converted to the Nissan diesel when I bought it in 2002, far enough for me to take over and fix the little things.....

Thanks for the book, in advance!!!

This and the AIR system to pump air in the exhaust + EGR created a mess of hoses and vacuum lines


Sent from my iPhone using Tapatalk

So did the 1985, I-4, 2.5 L, carburetor jeeps have a microprocessor computer? The drawings seem to say yes? They also seem to claim an O2 sensor? But I do not see separate drawings in the Haynes manual for throttle body injection versus carburetor rigs????

Did you get this sorted?
Some places say the 4cy wranglers had the same system as the early 4cy XJ , maybe that will be easier to find.

I'm confused because the 2.8 lump had two versions one with no computer and one with all the years (84-86) and both are in the electrics trouble shooting book the 4cy only has the one set of schematics.



Sent from my iPhone using Tapatalk

Not yet, but I am hoping it is a bad head light switch, or crossed wiring at the switch, as the short load increases when I go from head lights or just running lights ON, to the off spot. But it does pull power at odd places other than the running lights like a relay and vacuum valve relay under the hood that are ancient parts of the Emis, controls for the prior engine. Been too busy with other stuff, and way too hot and humid lately for this old body.

Green Mesa XJ said:

Did you get this sorted?
Some places say the 4cy wranglers had the same system as the early 4cy XJ , maybe that will be easier to find.

I'm confused because the 2.8 lump had two versions one with no computer and one with all the years (84-86) and both are in the electrics trouble shooting book the 4cy only has the one set of schematics.



Sent from my iPhone using Tapatalk

Click to expand...

Yeah. Where I'm at we are baking 78 degree nights and the humidity is 80-90 percent on a good day. Got forecasts of a huge amount of rain possible for the next ten days.

Anyway That's a weird power problem. Pulling power in strange places is a puzzler. Did it have cruse control? Had a fifth avenue that shorted out drawing power constantly, and a Taurus that tried to kill my sister accelerating like a SOB, she had to stand on the brakes to stop it.


Sent from my iPhone using Tapatalk