SaturnFans.com
what's new (beta) - classifieds - forums - photos


Go Back   SaturnFans.com Forums > Models > Saturn Vue > 2008 Vue
Register FAQ Members List Groups Calendar Chat Room Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Display Modes
Old 06-20-2016, 04:48 PM   #1
mjmcginty
New Member
mjmcginty is on a distinguished road
 
Join Date: Jun 2016
Location: Central California Coast
Posts: 4

2008 VUE 3.6L
Default Brake lights, backup lights out

I have checked the bulbs, the brake light switch and the STOP LP fuse with a meter, and I replaced the STOP LP RLY relay (based on bad advise) all to no avail.

When the brake pedal is depressed I can't hear or feel the relay click, which tells me some logic is inhibiting the brake light "on" condition tree.

In theory it could be a wiring/connection problem between the switch and the board, but that wouldn't explain why the reverse lights also do not work.

So my question is, under what set of conditions would the onboard computer decide to not turn the brake lights on (even though the brake switch is actuated) AND to not turn the reverse lights on (even though the reverse switch is actuated)?

(Have any flow diagrams for the system's program ever been published?)

TIA

REWARD EXCELLENCE!

Add to mjmcginty's Reputation
Rate the quality of this post and help mjmcginty reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
mjmcginty is offline   Reply With Quote
SaturnFans.com Sponsored Links
Old 06-20-2016, 08:57 PM   #2
billysvue
Master Member
billysvue is a jewel in the roughbillysvue is a jewel in the roughbillysvue is a jewel in the rough
 
Join Date: Aug 2012
Location: san diego
Posts: 4,355

2005 VUE 2.2L
Default Re: Brake lights, backup lights out

Yes,there are electrical schematics/theory of operation/troubleshooting chart in a service manual.

Try ALL DATA for the gist of it.

...
'05 ,2.2L, FWD,5-speed stick with transaxle death rattle is history,,,
'17 Suby Forester

245216 mi. VUe is off to the dealer auction
I'm a secondhand vegetarian.
Cows eat grass, I eat cows.

REWARD EXCELLENCE!

Add to billysvue's Reputation
Rate the quality of this post and help billysvue reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
billysvue is offline   Reply With Quote
Old 06-21-2016, 10:40 AM   #3
far2grumpy
Master Member
far2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to behold
 
far2grumpy's Avatar
 
Join Date: Oct 2008
Location: Cedar Rapids, IA
Posts: 8,121
 

2005 VUE 3.5L
2007 VUE 3.5L
Default Re: Brake lights, backup lights out

Quote:
Originally Posted by mjmcginty View Post
I have checked the bulbs, the brake light switch and the STOP LP fuse with a meter, and I replaced the STOP LP RLY relay (based on bad advise) all to no avail.

When the brake pedal is depressed I can't hear or feel the relay click, which tells me some logic is inhibiting the brake light "on" condition tree.

In theory it could be a wiring/connection problem between the switch and the board, but that wouldn't explain why the reverse lights also do not work.

So my question is, under what set of conditions would the onboard computer decide to not turn the brake lights on (even though the brake switch is actuated) AND to not turn the reverse lights on (even though the reverse switch is actuated)?

(Have any flow diagrams for the system's program ever been published?)

TIA
I suspect you've solved the mystery by now but just in case ... here's FSM extract and a couple of wiring diagrams ... they're making the simple things more difficult as time goes by.

Just a thought ... have you verified the CHMSL/BKUP fuse is good?

[U]Stop Lamps[/U]

The body control module (BCM) is responsible for controlling the stop lamps. When the driver presses the brake pedal, the BCM will receive a signal from the brake switch. The BCM then supplies battery positive voltage to both left and right stop lamp assemblies and to the center high mounted stop lamp (CHMSL).

Backup Lamps

The CHMSL/BKUP fuse in the instrument panel (I/P) fuse block supplies battery positive voltage to the body control module (BCM). When the driver places the gear selector in to the REVERSE position, the powertrain control module (PCM) sends a class 2 message to the BCM. The BCM then applies battery positive voltage to the backup lamp supply voltage circuit. The left backup lamp is grounded at G401 and the right backup lamp is grounded at G402.
Attached Images
File Type: jpg 08 Vue Stop Lamps.jpg (85.8 KB, 14 views)
File Type: jpg 08 Vue Backup Lamps.jpg (159.9 KB, 11 views)

...
I try to visit forum often but suggest you use private messages if in a rush (comes to cell) and include email address for extracts. I seldom check visitor messages so please don't use.

REWARD EXCELLENCE!

Add to far2grumpy's Reputation
Rate the quality of this post and help far2grumpy reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
far2grumpy is offline   Reply With Quote
Old 06-28-2016, 10:34 PM   #4
mjmcginty
New Member
mjmcginty is on a distinguished road
 
Join Date: Jun 2016
Location: Central California Coast
Posts: 4

2008 VUE 3.6L
Default Re: Brake lights, backup lights out

Quote:
Originally Posted by far2grumpy View Post
I suspect you've solved the mystery by now but just in case ... here's FSM extract and a couple of wiring diagrams ... they're making the simple things more difficult as time goes by.
Thanks for replying, I appreciate your help. Actually, no I have not solved it. For years I've thought autolamp was a great feature, now I'm not so sure.

Quote:
Originally Posted by far2grumpy View Post
Just a thought ... have you verified the CHMSL/BKUP fuse is good?
Is there a third fuse panel (besides the ones in the engine compartment and on the passenger side under the dash)? I did check the STOP LP fuse, and every fuse prefixed with BCM, as well as all of the 10A fuses in the engine compartment. I didn't see any labeled CHMSL.

I do suspect it is a blown fuse though, I pulled the STOP LP RLY and jumpered the contacts with a piece of wire, no lights. For a reality check I did the same thing to HDLP HI RLY and the headlights lit as expected.

I guess I could go brute force and check every fuse... wonder what it would take to engineer a fuse that we could tell at a glance it was blown or broken?

Anyways thanks again for your time... really dreading taking it in, the local GM dealer here sucks, every time I go there I get the sensation of handcuffs and pants around my ankles.

Quote:
Originally Posted by far2grumpy View Post
[U]Stop Lamps[/U]

The body control module (BCM) is responsible for controlling the stop lamps. When the driver presses the brake pedal, the BCM will receive a signal from the brake switch. The BCM then supplies battery positive voltage to both left and right stop lamp assemblies and to the center high mounted stop lamp (CHMSL).

Backup Lamps

The CHMSL/BKUP fuse in the instrument panel (I/P) fuse block supplies battery positive voltage to the body control module (BCM). When the driver places the gear selector in to the REVERSE position, the powertrain control module (PCM) sends a class 2 message to the BCM. The BCM then applies battery positive voltage to the backup lamp supply voltage circuit. The left backup lamp is grounded at G401 and the right backup lamp is grounded at G402.

REWARD EXCELLENCE!

Add to mjmcginty's Reputation
Rate the quality of this post and help mjmcginty reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
mjmcginty is offline   Reply With Quote
Old 06-29-2016, 11:32 AM   #5
far2grumpy
Master Member
far2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to behold
 
far2grumpy's Avatar
 
Join Date: Oct 2008
Location: Cedar Rapids, IA
Posts: 8,121
 

2005 VUE 3.5L
2007 VUE 3.5L
Default Re: Brake lights, backup lights out

I'm trying to find more diagrams to see if there really is a CHMSL fuse (as mentioned in text).

BTW - does CHMSL light when brakes are pressed? It appears to not be relay controlled but does use same ground point as TAIL/STOP/BKUP lamps.

Speaking of TAIL lamps - do they operate normally? If yes - would probably eliminate bad grounds.

...
I try to visit forum often but suggest you use private messages if in a rush (comes to cell) and include email address for extracts. I seldom check visitor messages so please don't use.

REWARD EXCELLENCE!

Add to far2grumpy's Reputation
Rate the quality of this post and help far2grumpy reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
far2grumpy is offline   Reply With Quote
Old 06-29-2016, 01:51 PM   #6
far2grumpy
Master Member
far2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to behold
 
far2grumpy's Avatar
 
Join Date: Oct 2008
Location: Cedar Rapids, IA
Posts: 8,121
 

2005 VUE 3.5L
2007 VUE 3.5L
Default Re: Brake lights, backup lights out

There is no separate CHMSL fuse.

Refer to attached thumbnail to make sure BACKUP/STOP fuse is OK.

I'll mark-up and post another diagram to help locate BCM connection.
Attached Images
File Type: jpg BACKUP-STOP - Edit.jpg (115.4 KB, 9 views)

...
I try to visit forum often but suggest you use private messages if in a rush (comes to cell) and include email address for extracts. I seldom check visitor messages so please don't use.

REWARD EXCELLENCE!

Add to far2grumpy's Reputation
Rate the quality of this post and help far2grumpy reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
far2grumpy is offline   Reply With Quote
Old 06-29-2016, 02:54 PM   #7
far2grumpy
Master Member
far2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to behold
 
far2grumpy's Avatar
 
Join Date: Oct 2008
Location: Cedar Rapids, IA
Posts: 8,121
 

2005 VUE 3.5L
2007 VUE 3.5L
Default Re: Brake lights, backup lights out

Thumbnail should help you locate BCM and connector X4.

Send PM if you'd like speedy response - it'll come to my cell as email.
Attached Images
File Type: jpg BCM X4 - Edit.jpg (106.9 KB, 8 views)

...
I try to visit forum often but suggest you use private messages if in a rush (comes to cell) and include email address for extracts. I seldom check visitor messages so please don't use.

REWARD EXCELLENCE!

Add to far2grumpy's Reputation
Rate the quality of this post and help far2grumpy reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
far2grumpy is offline   Reply With Quote
Old 06-29-2016, 02:56 PM   #8
mjmcginty
New Member
mjmcginty is on a distinguished road
 
Join Date: Jun 2016
Location: Central California Coast
Posts: 4

2008 VUE 3.6L
Default Re: Brake lights, backup lights out

Quote:
Originally Posted by far2grumpy View Post
I'm trying to find more diagrams to see if there really is a CHMSL fuse (as mentioned in text).

BTW - does CHMSL light when brakes are pressed? It appears to not be relay controlled but does use same ground point as TAIL/STOP/BKUP lamps.

Speaking of TAIL lamps - do they operate normally? If yes - would probably eliminate bad grounds.
No CHMSL does not light. (True CHSML isn't powered via the relay, it's driven directly by the BCM, probably a MOSFET or triac, since it's LED it doesn't draw as much current, no need for a relay.)

I just bought a "Service Workshop Repair manual" online, waiting for the email. I bought a Haynes manual the day it broke (middle of a trip) but it's nearly worthless, schematics are obviously incomplete...

And problem solved! BCMV4 was missing.

REWARD EXCELLENCE!

Add to mjmcginty's Reputation
Rate the quality of this post and help mjmcginty reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
mjmcginty is offline   Reply With Quote
Old 06-29-2016, 04:22 PM   #9
far2grumpy
Master Member
far2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to beholdfar2grumpy is a splendid one to behold
 
far2grumpy's Avatar
 
Join Date: Oct 2008
Location: Cedar Rapids, IA
Posts: 8,121
 

2005 VUE 3.5L
2007 VUE 3.5L
Default Re: Brake lights, backup lights out

BCM VB4 was AWOL?

What a mean trick to play on someone.

...
I try to visit forum often but suggest you use private messages if in a rush (comes to cell) and include email address for extracts. I seldom check visitor messages so please don't use.

REWARD EXCELLENCE!

Add to far2grumpy's Reputation
Rate the quality of this post and help far2grumpy reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
far2grumpy is offline   Reply With Quote
Old 06-29-2016, 10:48 PM   #10
mjmcginty
New Member
mjmcginty is on a distinguished road
 
Join Date: Jun 2016
Location: Central California Coast
Posts: 4

2008 VUE 3.6L
Default Re: Brake lights, backup lights out

Quote:
Originally Posted by far2grumpy View Post
BCM VB4 was AWOL?

What a mean trick to play on someone.
Right? It takes a fair amount of force to pull them, I don't see how one could fall out. The cover was off the inside fuse panel when I was told the lights were out but I didn't think much of it at the time.

So maybe a neighbor needed a 15A fuse, noticed my car was unlocked and "borrowed" it? I would've happily given them the spare. My mind: blown.

In any case, thanks for all your help, I appreciate it! The answer was actually in the first thing you attached... forest/trees syndrome I guess.

I do like the service manual though, it was worth buying... and I found a use for the Haynes manual too, its pages burn quite nicely, it will come in handy whenever I bbq.

REWARD EXCELLENCE!

Add to mjmcginty's Reputation
Rate the quality of this post and help mjmcginty reputation points. Click the reputation button near the bottom left corner of this message box. Thank you!
mjmcginty is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Running cable for backup camera & tapping into reverse lights for backup sensors shaxs Vue General 19 08-02-2018 02:07 PM
No tail lights, dash lights, auto headlights but have brake lights Troubled Saturn L-Series Tech 2 12-23-2015 07:11 PM
Backup lights help Linus S-Series Tech 9 03-18-2015 10:25 AM
No Backup Lights blackbeard S-Series Tech 4 01-13-2014 10:23 AM
No backup lights Spacepope Ion General 1 02-04-2007 01:24 PM


All times are GMT -4. The time now is 12:53 AM.

Advanced Forum Search | Advanced Photo Search


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
SaturnFans.com. The Saturn Enthusiasts Site.