fj 80 electrical problems

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Joined
Sep 12, 2022
Messages
7
Location
Illinois
Long time follower first time poster: Ive got a 1991 fj80 that i recently swapped out the dash, prior to the swap everything worked just fine. Now i have no running lights and brake lights, the heater blower motor is not working and the alternator light, the trans temp light and the brake light is on on the dash. I can jump power to the fuses and make every thing work but not stay working. when i did the dash swap I use all the original componets and only swapped the dash and dash pad out, nothing else
Some of this is related to the chp/lp relay under the hood,swapped that out with another relay still the same.. Please advise, I'm at the end of my fuse here!!!!
 
These are really hard to solve remotely but I will try.

Did you check everything?

Just kidding

You might have blown your FL MAIN 2.0L Fusible Link, because it is provides power to headlights, brake lights, heater, and from the alternator.

1743288513452.png


 
You have three, not two, fusible links: AM1, AM2, Main.

FL AM1 1.25B
FL AM2 0.3P
FL MAIN 2.0L

It is the 3rd one that provides power to everything that you mentioned. When running, is the voltage at the battery above 12.6V?

Also, check the ground on the driver's kick panel: identified as ID in the EWD.
 
You have three, not two, fusible links: AM1, AM2, Main.

FL AM1 1.25B
FL AM2 0.3P
FL MAIN 2.0L

It is the 3rd one that provides power to everything that you mentioned. When running, is the voltage at the battery above 12.6V?

Also, check the ground on the driver's kick panel: identified as ID in the EWD.
I checked the ground its good, clean and tight. ive got 11.9 volts at the battery and going through all 3 fusable links at the battery, voltage does not go up when running, its staying the same or dropping a couple of tenths of a volt at 11.7 or 11.8 ive got some fuses that have no power going to them like brake, tail, fog, stop and ign in the fuse panel under the dash
 
Your battery should be at 12.6V when the motor is not running and well above 13V when the motor is running. 11.9V = problem.

To me, not getting above 12.6V when the motor is running tells me power is not flowing from the Alternator to the Battery. Something is blown.

There is a 50A fuse and a 7.5A charge fuse. Both in the Relay Block No. 2, which is on the driver's fender.

1743295064355.png
 
Your battery should be at 12.6V when the motor is not running and well above 13V when the motor is running. 11.9V = problem.

To me, not getting above 12.6V when the motor is running tells me power is not flowing from the Alternator to the Battery. Something is blown.

There is a 50A fuse and a 7.5A charge fuse. Both in the Relay Block No. 2, which is on the driver's fender.

View attachment 3872672
the 50 amp fuse checks out as getting continuity through it and power to the number 1 lug side with a test light. the fuse labeled charge has no power going to it but when I put the test light on terminal one it makes the charge light relay click , when I pull thst fuse out the alt light on dash and at trans temp light goes out
 
I think that is the way the dash fuse light works but probe the backside of the 7.5 amp charge light fuse for continuity with an ohm meter.
 
I think that is the way the dash fuse light works but probe the backside of the 7.5 amp charge light fuse for continuity with an ohm meter.
the fuse checks out good as it has continuity going through it Im pretty frustrated at this point as i had no electrical issues before this project i really appreciate your help!!!!
 
I think you have a wiring issue between the alternator, relay block #2, and the battery. I mean, you could have a bad alternator.

You should be getting close to 14V when the motor is running. Check the voltage at the alternator, while the motor is running, and work your way to the Relay Block #2, and finally to the battery. Check all along the way for voltage close to 14V..and then if you see below 12V, you know the problem is before there.
 
I think you have a wiring issue between the alternator, relay block #2, and the battery. I mean, you could have a bad alternator.

You should be getting close to 14V when the motor is running. Check the voltage at the alternator, while the motor is running, and work your way to the Relay Block #2, and finally to the battery. Check all along the way for voltage close to 14V..and then if you see below 12V, you know the problem is before there.
im done for today and will try some more tomorrow and ill report back on what i find thank you again!!
 
the alternator light, the trans temp light and the brake light is on on the dash.
That's screaming out alternator or charging circuit. Most likely alternator.
Dash christmas tree lights.
 

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