The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > General Truck Forums > Electrical

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 07-06-2019, 10:22 PM   #1
blazintowers
Registered User
 
blazintowers's Avatar
 
Join Date: Sep 2009
Location: saugus, ca
Posts: 68
71 blazer - green ground wire

hello everyone,
wanted to know if anyone knows where this green ground wire is supposed to be terminated? it comes from the harness behind the distributor and is long enough to route to the front of the motor? I know I could probably ground anywhere but does anyone know what its for?


71 blazer

ac equipped
Attached Images
  
blazintowers is offline   Reply With Quote
Old 07-06-2019, 10:31 PM   #2
blazintowers
Registered User
 
blazintowers's Avatar
 
Join Date: Sep 2009
Location: saugus, ca
Posts: 68
Re: 71 blazer - green ground wire

sorry for the sideways pics, I swear they were correctly oriented before I attached them!
blazintowers is offline   Reply With Quote
Old 07-10-2019, 11:44 AM   #3
Wrenchbender Ret
Registered User
 
Join Date: Oct 2005
Location: Lenexa, Kansas
Posts: 4,716
Re: 71 blazer - green ground wire

I don't think it is a ground wire. It probably goes to a temperature sending unit or possible compressor clutch.
George
Wrenchbender Ret is offline   Reply With Quote
Old 07-10-2019, 12:03 PM   #4
blazintowers
Registered User
 
blazintowers's Avatar
 
Join Date: Sep 2009
Location: saugus, ca
Posts: 68
Re: 71 blazer - green ground wire

Thanks for the reply Wrenchbender. I thought it was a ground due to the wire being crimped to that metal tab. I will trace it out and see where the other end terminates at to see if it goes to a circuit.

Todd
blazintowers is offline   Reply With Quote
Old 07-10-2019, 02:04 PM   #5
rpmerf
Registered User
 
rpmerf's Avatar
 
Join Date: Feb 2011
Location: Parkville, MD
Posts: 711
Re: 71 blazer - green ground wire

Agree with temp sender. My temp sender wire has the same bracket on it.

http://outintheshop.com/faq/wiring/w...s/image002.jpg
20DG in the schematic
__________________
1970 C20 Custom Camper - 350, TH350
1997 GMC Suburban
1994 Acura Integra GSR
1987 Dodge Daytona Shelby Z
rpmerf is offline   Reply With Quote
Old 07-10-2019, 08:50 PM   #6
blazintowers
Registered User
 
blazintowers's Avatar
 
Join Date: Sep 2009
Location: saugus, ca
Posts: 68
Re: 71 blazer - green ground wire

hello rpmerf, you don't happen to have a pic of the bracket connected to your sensor do yah? I just looked at mine again and found another green wire that is used for my temp sensor so I am even more confused...Also the wiring diagram you attached is different than the one I have. Do you know if there are different wiring diagrams for trucks and blazers? I wouldn't think so but mine is definitely different and it is from the original service manual.
blazintowers is offline   Reply With Quote
Old 07-10-2019, 09:18 PM   #7
blazintowers
Registered User
 
blazintowers's Avatar
 
Join Date: Sep 2009
Location: saugus, ca
Posts: 68
Re: 71 blazer - green ground wire

here is the diagram I have, not sure if I am using the correct one but it matches my blazer wiring. notice the relays I have circled . now I also notice two dark green wires running to two different sensors, one HOT and one COLD.
Does any one know what the "SW ASM" stands for in the "ENG TEMP SW ASM COLD"?

EDIT:
Ok, thanks for the info, looks like circuit 35 and 159C for two separate sensors
Attached Images
 

Last edited by blazintowers; 07-10-2019 at 11:25 PM.
blazintowers is offline   Reply With Quote
Old 07-12-2019, 09:07 AM   #8
rpmerf
Registered User
 
rpmerf's Avatar
 
Join Date: Feb 2011
Location: Parkville, MD
Posts: 711
Re: 71 blazer - green ground wire

I don't. When I got the truck, the wire was running down the frame rail and the bracket was not connected. Currently have it going over the valve cover. I think it originally gets bolted to the block, kind of following the spark plug wires under the exhaust. Just a guess though.
__________________
1970 C20 Custom Camper - 350, TH350
1997 GMC Suburban
1994 Acura Integra GSR
1987 Dodge Daytona Shelby Z
rpmerf is offline   Reply With Quote
Old 07-12-2019, 10:08 AM   #9
VetteVet
Msgt USAF Ret
 
VetteVet's Avatar
 
Join Date: Jan 2005
Location: Kalamazoo, Michigan
Posts: 8,285
Re: 71 blazer - green ground wire

Here is a possibility. you might want to do some research on the TCS, aka- transmission controlled spark.

http://67-72chevytrucks.com/vboard/s...ntrolled+spark
__________________
VetteVet

metallic green 67 stepside
74 corvette convertible
1965 Harley sportster
1995 Harley wide glide

Growing old is hell, but it beats the alternative.
VetteVet is offline   Reply With Quote
Old 07-12-2019, 03:26 PM   #10
Wrenchbender Ret
Registered User
 
Join Date: Oct 2005
Location: Lenexa, Kansas
Posts: 4,716
Re: 71 blazer - green ground wire

Some vehicles back then had a hot light & cold light. The sensor had 2 terms. One wire was dark green & the other was a light green. The cold light would go out when the temp. of the engine started to warm up. There was no use turning on the heater until the green light went out
George
Wrenchbender Ret is offline   Reply With Quote
Old 07-12-2019, 08:28 PM   #11
blazintowers
Registered User
 
blazintowers's Avatar
 
Join Date: Sep 2009
Location: saugus, ca
Posts: 68
Re: 71 blazer - green ground wire

thanks for the replies and great information everyone! I can see now that they do run to the two sensors - hot and cold, via circuits 35 and 159c.

Where do you find all the codes for the abbreviations? looking for what SW ASM stands for, its on the wire diagram above.
blazintowers is offline   Reply With Quote
Old 07-12-2019, 09:38 PM   #12
Wrenchbender Ret
Registered User
 
Join Date: Oct 2005
Location: Lenexa, Kansas
Posts: 4,716
Re: 71 blazer - green ground wire

The ASM is a switch that only allows the vacuum advance to work in high gear with an auto trans. It is an early emission control device & is best left bypassed.
Wrenchbender Ret is offline   Reply With Quote
Old 07-14-2019, 11:09 AM   #13
blazintowers
Registered User
 
blazintowers's Avatar
 
Join Date: Sep 2009
Location: saugus, ca
Posts: 68
Re: 71 blazer - green ground wire

Quote:
Originally Posted by Wrenchbender Ret View Post
The ASM is a switch that only allows the vacuum advance to work in high gear with an auto trans. It is an early emission control device & is best left bypassed.
So when you say bypassed, do you typically leave the original parts in place and just disconnect them, or remove the stuff you don't need to clean up the engine bay? I'm doing the HEI wire to replace the resistor wire and trying to tidy up a bit...Thanks ALL again !
blazintowers is offline   Reply With Quote
Reply

Bookmarks

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


All times are GMT -4. The time now is 04:39 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Copyright 1997-2013 67-72chevytrucks.com