GM Engine & Exhaust Performance EFI | GEN I/GEN II/GEN III/GEN IV Engines |Small Block | Big Block |

O2 sensor heater circuit problem

Thread Tools
 
Search this Thread
 
Old Mar 24, 2020 | 03:13 PM
  #1  
dry_kill's Avatar
Thread Starter
TECH Fanatic
iTrader: (12)
 
Joined: Sep 2005
Posts: 1,777
Likes: 0
From: houston tx
Default O2 sensor heater circuit problem

Hey fellas, should start off by saying this is actually a 87 El Camino with a 5.3 ls swap. I haven't had much luck on the gbody forums so I'm posting here.

Been having a check engine light on the Camino for some time now. I should note this isn't the factory check engine light. It's on my Dakota digital dash where it's popping up.
​​The engine light says both oxygen sensors heater circuits. Now I don't know much about wiring, and I did not build the harness nor install the harness for my car.


The guy that installed it for me is now nowhere to be found and I'm stuck with this annoying light on my dash. I have replaced both sensors but still having same issue. Here's a few pics of the shitty wiring this guy did and a pic of the code it's throwing








Reply
Old Mar 24, 2020 | 03:37 PM
  #2  
RB04Av's Avatar
TECH Enthusiast
5 Year Member
 
Joined: Jul 2018
Posts: 663
Likes: 235
Default

The wiring doesn't look all that terrible to me. I've seen FAR worse. (better too, but yeah...) Looks kinda like he just transplanted the whole LM7 harness over, and used some convenient fuse block from some other vehicle that had enough fuses and then pigtailed them to the LM7 harness, which is probably as reasonable and sanitary a method as there is, short of remanufacturing a whole new one ($$$$$$$$$$$$$ comparatively speaking).

Both O2 sensor heater ckts showing a code sounds like a fuse issue. They both run off of fuse O2A in an original LM7. There are 2 pink wires coming from that fuse. It's not impossible that there's a splice involving those, in your 4th pic. Check to see if there's 12V on those, and follow them back toward the fuse block.
Reply
Old Mar 24, 2020 | 04:36 PM
  #3  
dry_kill's Avatar
Thread Starter
TECH Fanatic
iTrader: (12)
 
Joined: Sep 2005
Posts: 1,777
Likes: 0
From: houston tx
Default

When you say follow them to the fuse block, are you talking about the Camino original fuse box under the dash or the little fuse box in my pictures? And do I check the pink wires in my 4th pic?
Reply
Old Mar 24, 2020 | 04:50 PM
  #4  
RB04Av's Avatar
TECH Enthusiast
5 Year Member
 
Joined: Jul 2018
Posts: 663
Likes: 235
Default

Since that's part of the new harness, and the 87 didn't have heated sensors (or 2 of them), they should get their power from the new fuse block.

Yes it looks like those pink wires might be spliced to some wire coming off of that fuse block, meaning that inside that tape, there might be a solder joint. See if there's 12V there.
Reply
Old Mar 24, 2020 | 05:14 PM
  #5  
dry_kill's Avatar
Thread Starter
TECH Fanatic
iTrader: (12)
 
Joined: Sep 2005
Posts: 1,777
Likes: 0
From: houston tx
Default

Ok I will check it out, thanks for the help
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
RedXray
PROJECTS GALLERY
788
Mar 17, 2026 03:08 PM
Snowstorm
GMT 900 Trucks General Discussion
5
Oct 1, 2019 08:43 PM
Go5.3tt06
GMT 800 & Older GM General Discussion
9
Jan 25, 2012 03:51 PM
gmforlife
GM Drivetrain & Suspension
13
Apr 2, 2007 05:02 PM




All times are GMT -5. The time now is 09:41 PM.