1977 CJ5 wiring / lights help - JeepForum.com
 
LinkBack Thread Tools
post #1 of 13 Old 09-11-2021, 11:08 AM Thread Starter
sourkraus
Registered User
 
sourkraus's Avatar
1977 CJ5 
 
Join Date: Jun 2020
Posts: 9
1977 CJ5 wiring / lights help

All - I’m hoping to get some help with some things did electrical behavior with the Jeep’s lights. Here’s a listing of the oddities:
1. High beams don’t work (low beams work fine)
2. Brake lights don’t work (tail lights work fine)
3. Instrument panel lights don’t work

This seems like relatively new behavior. I’ve checked fuses and nothing seems out of sort.

Any thoughts on source of the problem or how to begin troubleshooting.

Thanks in advance.


=======
1977 CJ5; AMC304; 3 Speed; 33x12.50s
sourkraus is offline  
Sponsored Links
Advertisement
 
post #2 of 13 Old 09-11-2021, 07:10 PM
JEEPFELLER
Registered User
 
JEEPFELLER's Avatar
1977 CJ5 
 
Join Date: Dec 2015
Location: W. South Carolina
Posts: 1,615
Garage
Something that just started?

OR

Was like this when you acquired it?

Do you know how to operate the dimmer switch?

----JEEPFELLER
JEEPFELLER is offline  
post #3 of 13 Old 09-11-2021, 07:43 PM Thread Starter
sourkraus
Registered User
 
sourkraus's Avatar
1977 CJ5 
 
Join Date: Jun 2020
Posts: 9
It’s a new problem.

Good call on the dimmer. However, I’ve checked that without avail.


[iQUOTE=JEEPFELLER;41353955]Something that just started?

OR

Was like this when you acquired it?

Do you know how to operate the dimmer switch?

----JEEPFELLER[/QUOTE]

=======
1977 CJ5; AMC304; 3 Speed; 33x12.50s
sourkraus is offline  
 
post #4 of 13 Old 09-11-2021, 08:35 PM
John Strenk
Moderator
 
John Strenk's Avatar
1976 CJ5 
 
Join Date: Feb 2005
Location: Shalersville Ohio
Posts: 22,716
Quote:
Originally Posted by sourkraus View Post
It’s a new problem.

Good call on the dimmer. However, I’ve checked that without avail.
Does that mean the dimmer works fine?

Did all these circuits die at the same time?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I drive a Prius to save money and buy more Jeep Parts....
John Strenk is offline  
post #5 of 13 Old 09-11-2021, 09:16 PM
JEEPFELLER
Registered User
 
JEEPFELLER's Avatar
1977 CJ5 
 
Join Date: Dec 2015
Location: W. South Carolina
Posts: 1,615
Garage
I drew this a long time ago before learned how to use "MS Paint"

My whiny neighbor wanted to put a toggle switch on his dash to replace the floor switch.

I'm gonna use part of this for you to perform a test---forget the toggle end

At the top is the connector to the dimmer switch-------this is the only thing we are going to deal with

3 ports to plug in the dimmer-----the high or low beam wires may be/ can swap positions-----the floor dimmer don't care which side is which

The middle wire (on the connector) is Power from the dash light switch----this single wire powers both the high and low beams, BUT only one at at time

WE KNOW the low beams work, so the problem is SOMEWHERE from the dimmer switch on to the high beams.

Test one----take the connector loose and see if the dimmer or it's connectors are melted, the connector's brass inserts are not pushed back (not allowing a connection)

If so, most likely you need a dimmer or a pigtail connector

NOT THE PROBLEM? (YET)

We know the upper middle slot in the connector is the power

Grab a short piece of stranded wire (16 gauge or so---smaller may overheat

Have a helper tell you what the lights are doing.

Jump the center (power) to either outer slot (one at a time)

Turn on the light switch on the dash

Results?

Now jump to the other slot

Light switch on

Results?

At minimum the low beams should have worked (still)

If both high and low lit up (one at a time) Your dimmer switch is defective

If still no high beams

Maybe both high filaments are blown----sometimes you fail to see one is out, until the other one goes---try a different bulb if you have spare. Or remove the bulbs and test with a voltmeter

Bad connection/ break in the system before the bulbs

Weak or bad ground

This is a portion of a 1979 diagram that I colored from a manual----I eliminated everything except for "lighting" in these 2 diagrams to make "Lookin'" EZer (I have the full diagrams)

There was no "Legend" in the manual, so I kinda coded some of the wires "MY WAY" so I could keep track of the wires with tracer colors/ stripes----They are dashed lines (NOW) with the base color being the correct color/ the stripe unknown

Ask if you get confused

-------JEEPFELLER
Attached Thumbnails
HOW TO WIRE UP REMOTE DIMMER SWITCH.jpg   79 CJ lighting left side.jpg   79 CJ lighting right side.jpg  
JEEPFELLER is offline  
post #6 of 13 Old 09-11-2021, 09:30 PM
Rondawg80
Registered User
1980 CJ5 
 
Join Date: Feb 2017
Location: Ventura County
Posts: 58
Have you checked your grounds?? CJ grounds are really crappy!
Rondawg80 is offline  
post #7 of 13 Old 09-12-2021, 07:48 AM
mpulokas
Registered User
1977 CJ7 
 
Join Date: Dec 2018
Posts: 143
1) check and test the high/low beam switch on the floor w/ you multimeter(or test light) and report back. They are known to fail and need replacement. Ground and feed are all same path. I guess you could just have a weak ground but ill bet on the switch.

2) brake lights could be a few things. Check the switch at the pedal to make sure it works or even engaging with the proper adjustment. Then the problem could be in the turn signal switch in the steering column if the switch on the floor not getting juice. Or the harness wire is just bad. You have do some hard work of using that multi-meter at every step of the way to find where the breakdown is. I think it is unlikely a bad ground in this one as the rest of the light works and it shares the same ground (housing grounded to body) and nothing on the tail light would work (maybe!).

3) dash lights: I'll bet on the switch is bad or needs cleaned up but you got to check wires too. Lights under dash are all orange. Check the feed coming out of switch to see if you got juice there when on. If so then it is the wire and grounding gremlin.

If you can't use a multi-meter or test light you won't get far unless you just enjoy spending money replacing things one at a time with trial and error. We will be just guessing too. Let us know what you find.

- MAP
mpulokas is offline  
post #8 of 13 Old 09-12-2021, 07:52 AM
mpulokas
Registered User
1977 CJ7 
 
Join Date: Dec 2018
Posts: 143
Also get yourself the wiring diagram I made and posted to the dwg sticky post. I make it special for the 76/77. It is a high Res PDF file.

- MAP
mpulokas is offline  
post #9 of 13 Old 09-13-2021, 07:00 PM Thread Starter
sourkraus
Registered User
 
sourkraus's Avatar
1977 CJ5 
 
Join Date: Jun 2020
Posts: 9
Hey guys. Wanted to circle back. Huge thanks to jeepfeller and mpulokas.

I’ve made progress based on your diagnosis tips.

1. Brake lights - turns out this was a fuse after all. The tip of NOT checking grounds saved me a bunch of time. THANK YOU. The fuse appeared fine, but thought I’d start there and work back (vs chasing grounds) when I swapped it everything became operable.

2. High beams / dash lights - I removed the dimmer/headlamp switch and proved that everything would illuminate when I manually jumped the wires. I then checked the floor pedal and found that both high/low worked when jumping. I restored the foot pedal temporarily so wouldn’t have lose wires in the event I needed to drive her and, wouldn’t you know it, the floor pedal switch started working again. Can’t explain it…but it’s functioning again. Likewise, the dash lights are functioning. I’m wondering if the harness just wasn’t seated correctly.

3. Floor lights - still not functional. I can deal with this for now. At least Jeep is safe to drive again. I’ll troubleshoot this more later.

Thanks again for all the tips and the diagrams. The images I have were low res png. I might circle back in he future to request those high res pdf. No need today…but if this Jeep has taught me anything, they’ll be plenty of opportunities in the future. 🙂

Many thanks.

=======
1977 CJ5; AMC304; 3 Speed; 33x12.50s
sourkraus is offline  
post #10 of 13 Old 09-13-2021, 07:08 PM
John Strenk
Moderator
 
John Strenk's Avatar
1976 CJ5 
 
Join Date: Feb 2005
Location: Shalersville Ohio
Posts: 22,716
Could be one of the terminals inside the plug overheated and now is not making good contact. This can cause it to over heat again and you will loose your lights again. I would recommend replacing the terminals, they are easy to pull out of the plug with a thin screwdriver pushing gown the tab that holds it in place.

And going to a relay upgrade to take the load off the switch in the future.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


I drive a Prius to save money and buy more Jeep Parts....
John Strenk is offline  
post #11 of 13 Old 09-14-2021, 10:25 AM
mpulokas
Registered User
1977 CJ7 
 
Join Date: Dec 2018
Posts: 143
Quote:
Originally Posted by sourkraus View Post
Thanks again for all the tips and the diagrams. The images I have were low res png. I might circle back in he future to request those high res pdf. No need today…but if this Jeep has taught me anything, they’ll be plenty of opportunities in the future. 🙂

Many thanks.

See this thread, post #78
https://www.jeepforum.com/forum/f8/c...26/index6.html

- MAP
mpulokas is offline  
post #12 of 13 Old 09-24-2021, 12:39 PM Thread Starter
sourkraus
Registered User
 
sourkraus's Avatar
1977 CJ5 
 
Join Date: Jun 2020
Posts: 9
@mpulokas - Thanks for pointing me to your prior wiring post. I had previously found a similar wiring document but your color coding is hugely beneficial. I can see how having a .dwg with layers would be awesome, but the colors alone offer a tremendous improvement. Thanks for sharing!

=======
1977 CJ5; AMC304; 3 Speed; 33x12.50s
sourkraus is offline  
post #13 of 13 Old 09-25-2021, 09:42 AM
JEEPFELLER
Registered User
 
JEEPFELLER's Avatar
1977 CJ5 
 
Join Date: Dec 2015
Location: W. South Carolina
Posts: 1,615
Garage
Back to Mr. Dimmer

If the contacts in the connector got shoved back/ plastic melted and shoved back (as in my pic)/ or plastic melted and a connector up or down from it's normal position.

Lets say a "push" put two of the connections properly together, and the third (could be any one of them) "Is Touching" or is "barely pushed" into the female end.

It will work fine for minutes/ hours/ days---all the while it is heating up.

Then the most wonderful thing happens! Your head lights start blinking on and off! You attempt to counter this by hitting the dimmer, even over and over!

Now the lights are completely out. It's minus five outside and you are 40 miles away from everything.....not a tool one..

.....if you were more "McGyverish, you could cut the appropriate wires and twist it together, thus bypassing the connector,

Remember it is so cold that the cat you passed while ago has his tongue stuck to his butt. We can always buy a new pigtail..

...Or we can just take it loose and do a super inspection now!

-----JEEPFELLER
Attached Thumbnails
melted dimmer connectors.jpg  
JEEPFELLER is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome