Jump to content


Welcome to Ultimate Subaru Message Board, my lurker friend!

Welcome to Ultimate Subaru Message Board, an unparalleled Subaru community full of the greatest Subaru gurus and modders on the planet! We offer technical information and discussion about all things Subaru, the best and most popular all wheel drive vehicles ever created.

We offer all this information for free to everyone, even lurkers like you! All we ask in return is that you sign up and give back some of what you get out - without our awesome registered users none of this would be possible! Plus, you get way more great stuff as a member! Lurk to lose, participate to WIN*!
  • Say hello and join the conversation
  • Subscribe to topics and forums to get automatic updates
  • Get your own profile and make new friends
  • Classifieds with all sorts of Subaru goodies
  • Photo hosting in our gallery
  • Meet other cool people with cool cars
Seriously, what are you waiting for? Make your life more fulfilling and join today! You and your Subaru won't regret it, we guarantee** it.

* The joy of participation and being generally awesome constitutes winning
** Not an actual guarantee, but seriously, you probably won't regret it!

Serving the Subaru Community since May 18th, 1998!

Guest Message by DevFuse
 

Photo
- - - - -

86 Brat tail light and fuel gauge issues

brat electrical gremlins

  • Please log in to reply
10 replies to this topic

#1 Greenley

Greenley

    EA81 Nut

  • Members
  • 572 posts
  • Gardnerville : Reno/Tahoe

Posted 16 September 2013 - 04:12 PM

Vehicle: 1986 Brat GL Weber Carb swap, D/R 4spd

 

My dash indicator "brake dummy light" started rearing it's ugly head a while ago, in addition to the turn signal right arrow blinking as if the lamp was out

First thing i did was swap the bulbs out in the passenger side assembly, as this was where things were funky.

No change.

Cleaned the ground that is behind the bed access panel.

No dice.

 

The major problem is that the entire tail light assembly goes dark when applying the brake pedal, rather than illuminating brighter.

 

The fuel gauge has always been unreliable, but it stopped working completely after cleaning the ground wire.

 

Which may be a clue to someone as to the circuit in question.

 

Last night I checked the lamp connectors for corrosion, cleaned them, as well as inspected the wiring/pigtails for damage.

This got rid of the rapid turn signal indicator, for now...

 

I am kind of stumped as to what is going on here, and i dont feel like being pulled over for something so idiotic.

HELP! S.O.S.

 

Thanks in advance


Edited by Greenley, 16 September 2013 - 04:14 PM.


#2 subnz

subnz

    Advanced Member

  • Members
  • PipPipPip
  • 66 posts
  • Glenorchy New Zealand

Posted 16 September 2013 - 06:01 PM

sounds like a pinched wire  short somewhere in wiring harness in rear of vehicle (particularly in  braking circuit which could also be causing the other problems)  so suggest checking all wiring from cab rearward.

know this is irrelevant in this case but had a similar situation with another  car and found the rear seat was pinching wires.


Edited by subnz, 16 September 2013 - 06:11 PM.


#3 Cougar

Cougar

    Elite Master of the Subaru

  • Members
  • 6,342 posts
  • Anchorage

Posted 16 September 2013 - 07:03 PM

I think you have a grounding problem. Clean the battery to chassis ground and the ground for the taillights. You could also try running a temporary ground to the rear light to see if that proves a bad ground connection.



#4 Greenley

Greenley

    EA81 Nut

  • Members
  • 572 posts
  • Gardnerville : Reno/Tahoe

Posted 16 September 2013 - 07:48 PM

I think grounding problem. Clean the battery to chassis ground and the ground for the taillights.



Thanks Cougar, I have cleaned every ground in the engine bay,
in addition to running a 4 gauge ground from engine to chassis.
I believe the tail light ground wire to be the black wire behind the passenger side bed access panel. When I cleaned it up and reinstalled, that is when the fuel gauge went dead.

When you say run a ground wire to the affected lamp socket,
do you mean splicing into the existing one into a known ground?

What role does the pedal play in the circuit?
I ask, because just a minute ago, with the ignition turned to ACC, depressing the brake pedal was actuating the headlights (*confused*) and then it stopped.

Edited by Greenley, 16 September 2013 - 07:56 PM.


#5 Greenley

Greenley

    EA81 Nut

  • Members
  • 572 posts
  • Gardnerville : Reno/Tahoe

Posted 16 September 2013 - 07:58 PM

sounds like a pinched wire short somewhere in wiring harness in rear of vehicle (particularly in braking circuit which could also be causing the other problems) so suggest checking all wiring from cab rearward.
know this is irrelevant in this case but had a similar situation with another car and found the rear seat was pinching wires.


I'll look into a short, or pinched ground

#6 Greenley

Greenley

    EA81 Nut

  • Members
  • 572 posts
  • Gardnerville : Reno/Tahoe

Posted 18 September 2013 - 12:43 PM

broken ground wire was the issue here.

 

The fuel gauge is still not responding.



#7 Cougar

Cougar

    Elite Master of the Subaru

  • Members
  • 6,342 posts
  • Anchorage

Posted 18 September 2013 - 05:36 PM

The trouble you had with the brake lights and head lights pointed to a bad chassis ground connection as the trouble. Good job! The brake light switch is tied to power that passes it on to the brake lights and then to ground to turn on the lights when the pedal is depressed. If the grounding for those lights has a problem the circuit will seek any connection to ground it can find, which was through the head lights somehow.

 

The fuel sensor problem may be due to another faulty ground connection to it, so add a temporary connection to ground to the sensor ground and see if that changes things. If that doesn't make a difference then the power connection from the gauge to the sensor needs to be checked.



#8 TomRhere

TomRhere

    Certified BRAT nut!!!

  • Members
  • 4,030 posts
  • Hillsdale, Mi. USA

Posted 19 September 2013 - 03:48 AM

Sending unit for the fuel gage is on the rear of the tank, electrical connectors are there also. Check the connections for corrosion. Been the cause of my gage issues on all 5 of the BRATs I have owned.



#9 Greenley

Greenley

    EA81 Nut

  • Members
  • 572 posts
  • Gardnerville : Reno/Tahoe

Posted 19 September 2013 - 04:11 PM

Thank you for the help Cougar, you're always on point when it comes to electrical diagnosis!

 

Tom, you know the bullet connectors were incredibly corroded, they broke upon disconnection.

I ended up cutting out the bullet connectors and splicing them together.

Still no fuel gauge function.

 

I cant tell which wire is ground due to lack of access to a DVM or even a test light, (will search for that info)

So i think i'll try what Cougar suggested, and hard ground the sensor.

Even a low fuel light would be sufficient, as tracking mileage is pretty easy, but not always accurate with this brat.



#10 TomRhere

TomRhere

    Certified BRAT nut!!!

  • Members
  • 4,030 posts
  • Hillsdale, Mi. USA

Posted 20 September 2013 - 04:04 AM

Power for gage and Low Fuel Light is from fuse 12 on a Black/White wire.

 

At the sending unit, low fuel is White/Yellow wire, Gage is Black/Yellow.

 

Both gage and low fuel light are grounded thru the tank/body of vehicle.



#11 Cougar

Cougar

    Elite Master of the Subaru

  • Members
  • 6,342 posts
  • Anchorage

Posted 20 September 2013 - 01:59 PM

It sounds like it is time to purchase a meter.







Also tagged with one or more of these keywords: brat, electrical gremlins

0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users