gas gauge wiring on a retrofit Blazer tank question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

texascowboy593 · 03-04-2007, 07:54 PM

Figured I'd post this here due to the amount of Blazer tank installs on 67-72's:

I have a Blazer tank on my p/u and in the cab is an AutoMeter gas gauge. It's all hooked up at the gauge per manufacturer. My question is where do I hook up the green wire (see pics)? The ground is on the crossmember. The ground came with the tank. If I touch the green wire to the bronze colored post on the sending unit the gauge goes past full. I touch the wire anywhere else nothing happens...HELP!!! Thx so much, J

PanelDeland · 03-04-2007, 08:22 PM

Hopefully someone will chime in.I know there are two different ohm ratings for sending units but I don't know which is which.This could cause the problem.
Now for the help I can give TTT

byrd · 03-04-2007, 09:44 PM

do you know if the gauge and the sending unit are rated the same? sounds like a possible short to me

texascowboy593 · 03-04-2007, 10:22 PM

I'm pretty sure the are both 0-90 ohm. Maybe I should try a different ground than the crossmember. I know that the "past full" reading can be due to a bad ground...

724x4a/cchevy · 03-04-2007, 10:43 PM

I hate how microsoft paint turns ugly when you save it

Try touching the green wire to this brass terminal. Do you have any fuel in it? It wont spark or anything. These fuel gauges work by resisting the ground. If you touch it directly to the frame that is 0% resistance and the gauge goes full, the sending unit is just a variable resistor. 0 hms would probably be a full tank and 90 ohms would be empty.

texascowboy593 · 03-04-2007, 11:08 PM

The tank is 1/2 full (20 gal capacity, just put 10 in after being empty). Green wire makes the gauge go past full when touched to the brass terminal. I now know this is where it belongs. I suspect the ground is not the best. I just roughed up the metal down to bare under the screw on the crossmember (pic on 1st post) and it did no good. I guess I'll have to relocate it to a better spot and see if it makes any difference. I'll give it a shot in the morning. Thx for the replies guys!

cdowns · 03-04-2007, 11:24 PM

do you have a vent for your tank??// try a new ground for the sender unit

texascowboy593 · 03-05-2007, 01:00 PM

Just figured it out. I have a 0-30 ohm gauge and a 0-90 sender...Duh!

1972CheyenneSuper · 03-05-2007, 10:23 PM

Can you please post up some pictures of that tank install along with some details. What year blazer, which sending unit, is your truck a long box or short box, what are the tank straps used, what is the mounting location?

Sorry for the questions, but I am at the point of getting a fuel tank, and I'm having a hard time finding one to work with my Vortec.

texascowboy593 · 03-06-2007, 02:56 AM

Quote:

Originally Posted by 1972CheyenneSuper

Can you please post up some pictures of that tank install along with some details. What year blazer, which sending unit, is your truck a long box or short box, what are the tank straps used, what is the mounting location?

Sorry for the questions, but I am at the point of getting a fuel tank, and I'm having a hard time finding one to work with my Vortec.

PM sent...

03-04-2007, 07:54 PM	#1
texascowboy593 Registered User Join Date: Dec 2004 Location: Southeast Tx Posts: 1,302	gas gauge wiring on a retrofit Blazer tank question Figured I'd post this here due to the amount of Blazer tank installs on 67-72's: I have a Blazer tank on my p/u and in the cab is an AutoMeter gas gauge. It's all hooked up at the gauge per manufacturer. My question is where do I hook up the green wire (see pics)? The ground is on the crossmember. The ground came with the tank. If I touch the green wire to the bronze colored post on the sending unit the gauge goes past full. I touch the wire anywhere else nothing happens...HELP!!! Thx so much, J Attached Images __________________ "The rays of light thru the Shiner Bock bottle make me wanna turn the key and put down the throttle...and get lost down 35" - Jason Boland www.YouTube.com/user/593Films - Watch My Videos! 1977 Silverado K10 2014 Dodge Durango (Wife-mobile) 2008 Dodge Ram Lone Star Edition (Daily driver) Last edited by texascowboy593; 03-04-2007 at 07:55 PM.

03-04-2007, 08:22 PM	#2
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: gas gauge wiring on a retrofit Blazer tank question Hopefully someone will chime in.I know there are two different ohm ratings for sending units but I don't know which is which.This could cause the problem. Now for the help I can give TTT __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

03-04-2007, 10:22 PM	#4
texascowboy593 Registered User Join Date: Dec 2004 Location: Southeast Tx Posts: 1,302	Re: gas gauge wiring on a retrofit Blazer tank question I'm pretty sure the are both 0-90 ohm. Maybe I should try a different ground than the crossmember. I know that the "past full" reading can be due to a bad ground... __________________ "The rays of light thru the Shiner Bock bottle make me wanna turn the key and put down the throttle...and get lost down 35" - Jason Boland www.YouTube.com/user/593Films - Watch My Videos! 1977 Silverado K10 2014 Dodge Durango (Wife-mobile) 2008 Dodge Ram Lone Star Edition (Daily driver)

03-04-2007, 10:43 PM	#5
724x4a/cchevy Self-proclaimed LED man Join Date: Nov 2003 Location: Harrisburg, Missouri Posts: 1,021	Re: gas gauge wiring on a retrofit Blazer tank question I hate how microsoft paint turns ugly when you save it Try touching the green wire to this brass terminal. Do you have any fuel in it? It wont spark or anything. These fuel gauges work by resisting the ground. If you touch it directly to the frame that is 0% resistance and the gauge goes full, the sending unit is just a variable resistor. 0 hms would probably be a full tank and 90 ohms would be empty. __________________ My LED Website My Photobucket Album of LED's Ask me about hand-made custom L.E.D brake and reverse lights. <- LINK I also do LED: -Third Brake/Cargo -Brake (truck and burb) -Reverse (truck and burb) -67-68 Front Turn Signals -69-70 Front Turn Signals -71-72 Front Turn Signals -GMC Front Turn Signals I can also do custom lights for other vehicles....i did a set for a AMC Gremlin once Norwood Survivor Last edited by 724x4a/cchevy; 03-04-2007 at 10:46 PM.

03-04-2007, 11:08 PM	#6
texascowboy593 Registered User Join Date: Dec 2004 Location: Southeast Tx Posts: 1,302	Re: gas gauge wiring on a retrofit Blazer tank question The tank is 1/2 full (20 gal capacity, just put 10 in after being empty). Green wire makes the gauge go past full when touched to the brass terminal. I now know this is where it belongs. I suspect the ground is not the best. I just roughed up the metal down to bare under the screw on the crossmember (pic on 1st post) and it did no good. I guess I'll have to relocate it to a better spot and see if it makes any difference. I'll give it a shot in the morning. Thx for the replies guys! __________________ "The rays of light thru the Shiner Bock bottle make me wanna turn the key and put down the throttle...and get lost down 35" - Jason Boland www.YouTube.com/user/593Films - Watch My Videos! 1977 Silverado K10 2014 Dodge Durango (Wife-mobile) 2008 Dodge Ram Lone Star Edition (Daily driver)

03-04-2007, 11:24 PM	#7
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: gas gauge wiring on a retrofit Blazer tank question do you have a vent for your tank??// try a new ground for the sender unit __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

03-05-2007, 01:00 PM	#8
texascowboy593 Registered User Join Date: Dec 2004 Location: Southeast Tx Posts: 1,302	Re: gas gauge wiring on a retrofit Blazer tank question Just figured it out. I have a 0-30 ohm gauge and a 0-90 sender...Duh! __________________ "The rays of light thru the Shiner Bock bottle make me wanna turn the key and put down the throttle...and get lost down 35" - Jason Boland www.YouTube.com/user/593Films - Watch My Videos! 1977 Silverado K10 2014 Dodge Durango (Wife-mobile) 2008 Dodge Ram Lone Star Edition (Daily driver)

03-05-2007, 10:23 PM	#9
1972CheyenneSuper Registered User Join Date: Feb 2006 Location: ND Posts: 229	Re: gas gauge wiring on a retrofit Blazer tank question Can you please post up some pictures of that tank install along with some details. What year blazer, which sending unit, is your truck a long box or short box, what are the tank straps used, what is the mounting location? Sorry for the questions, but I am at the point of getting a fuel tank, and I'm having a hard time finding one to work with my Vortec.



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