Gain extra benefits by becoming a Supporting Member Click here find out how!
Classic Performance Products Classic Parts
American Auto Wire Classic Industries
Chevs of the 40sDanchuk Catalog
Hellwig Products IncPerformance Rod & CustomEcklers AutoMotive
Nu-Relics Power WindowsRain Gear Wiper Systems
Impala Bob's Bob's Chevy Trucks Bob's Chevelle Parts Bob's Classic Chevy



Username Post: 1975 C30 Fuel Tank Diagram        (Topic#353890)
Thumpit 
Poster
Posts: 60
Thumpit
Reg: 11-26-16
11-13-18 10:02 AM - Post#2751272    

Going to change out the fuel tank and sending unit as well on my 1975 C30 flat bed. Tank is on the passenger side. Gauge used to work until gas fell below 1\2 a tank, then it showed 1\2 till you ran out. Doesn't work at all now. Plus i took the tank off once to clean it and do a small hole repair and did not hook any of the wires back on the tank. Tired of leaking tank and no gauge. So I order a new set up.
Does anyone have a wire diagram for hooking up the sender with the wire or wires under the cab? Cant be over two or three. I don't remember.
Thanks for the help



 
junkman104 
Frequent Contributor
Posts: 1262

Age: 59
Loc: Murphy N.C.
Reg: 01-25-14
11-13-18 04:17 PM - Post#2751309    
    In response to Thumpit

Purple goes to gauge and black to ground, thats it.



 
gchemist 
Senior Chevytalk Moderator
Posts: 24533
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
11-14-18 04:18 PM - Post#2751414    
    In response to junkman104

Go here and download a factory manual for your truck.

http://forum.73-87chevytrucks.com/smforum/index.ph...

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles


 
Thumpit 
Poster
Posts: 60
Thumpit
Reg: 11-26-16
12-03-18 12:26 PM - Post#2753210    
    In response to gchemist

The single wiring plug that snaps down the sending unit is missing. Does anyone still make that end of the wiring connection or is there a way to make a connector that will work well. On the sending unit is just a single pole that the connector would attach to. I couldn't find an old truck to get one off.
Thanks



Edited by Thumpit on 12-03-18 01:01 PM. Reason for edit: No reason given.

 
gchemist 
Senior Chevytalk Moderator
Posts: 24533
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
12-03-18 02:19 PM - Post#2753225    
    In response to Thumpit

I have not looked at a fuel sending unit in years. Can you post a pic?

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles


 
junkman104 
Frequent Contributor
Posts: 1262

Age: 59
Loc: Murphy N.C.
Reg: 01-25-14
12-04-18 04:37 AM - Post#2753298    
    In response to gchemist

https://www.ebay.com/itm/Gas-Tank-Fuel-Sen ding-Unit-Pigtail-Wire-Ha rness-Connector-A-C-Compr essor-Chevy-/302628787151





 
gchemist 
Senior Chevytalk Moderator
Posts: 24533
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
12-04-18 06:14 AM - Post#2753306    
    In response to junkman104

Nice find. Eventually, I'll need to replace on unit on my truck. One tank reads off by a little.

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles


 
Thumpit 
Poster
Posts: 60
Thumpit
Reg: 11-26-16
12-04-18 07:15 AM - Post#2753315    
    In response to junkman104

Thanks.
The guage has always read from full to 1/2 a tank and then stopped at 1/2 a tank on the guage. I put a new tank and sending unit. I made a temp connector and hooked it up and the guage is still on 1/2 though the tank is empty right now.
Not sure if the guage need recalibration or fuse is blown.
Is the 'cluster fuse' where the guage gets it power?
I probably need to use a meter to check wires too but not to sure how to operate one.
Thanks again



 
gchemist 
Senior Chevytalk Moderator
Posts: 24533
gchemist
Loc: Austin, TX 78748
Reg: 05-09-00
12-04-18 08:13 AM - Post#2753324    
    In response to Thumpit

Did you download the factory manual? I think it has ohm readings for level indication.

'83 Silverardo XST - ZZ4 powered
'95 Jimmy SLT (Bought @131,814)
'96 GMC Jimmy LS Ret. @236651 miles


 
Thumpit 
Poster
Posts: 60
Thumpit
Reg: 11-26-16
12-04-18 09:24 AM - Post#2753333    
    In response to gchemist

I could probably find the readings on line. But with a meter I would like to test the hot wire (which is a 18 Tan according to my 75 wiring diagram) to check for power at the tank.
Would it just put the Hot lead on the Tan wire Connector and ground the Neg to the frame? And then put the settings on Oms?
Thanks



 
junkman104 
Frequent Contributor
Posts: 1262

Age: 59
Loc: Murphy N.C.
Reg: 01-25-14
12-04-18 04:05 PM - Post#2753378    
    In response to Thumpit

The sending unit is the ground. Shorted to ground the gauge should go past full.



 
Thumpit 
Poster
Posts: 60
Thumpit
Reg: 11-26-16
12-04-18 06:09 PM - Post#2753394    
    In response to junkman104

I shorted the connector to the ground and the gauge stayed on the 1/2 tank reading. Im gonna see if I can tell which fuse runs it and see if its blown. I also noticed that there are 2 Tan wires coming out of the lower left side of the fuse lock on the fire wall. One tan is suppose to be to the brakes, but I see a tan and green wire with plastic clips on the ends that are just hung out on the firewall and connected to nothing. But if i can trace the other tan one I want to check it for breaks. I dont think there is any power going to the connector or either the gauge is bad.
Would a test light work to see if there is power in the connector or is the power to small to light it up. I havent gotten a meter yet.
Thanks for the help. Im probably doing this all the hard way but will know better the next time.



 
Thumpit 
Poster
Posts: 60
Thumpit
Reg: 11-26-16
12-07-18 06:42 PM - Post#2753810    
    In response to Thumpit

Hey look guys, I just thought of something I forgot to mention. And I didn't think about it until I ran across an article about trouble shooting the fuel gauge through the ignition switch to be sure its getting power.
The 1975 truck came with a standard steering wheel without the tilt wheel. Well I ran across an 80's tilt steering at the salvage yard a couple years ago and pulled it and installed it in my 75. Even had the wiper controls on the turn signal, which does not work. I still use the slide switch on the dash panel. And come to think of it that's about the time the gauge stopped working altogether. Some of you guys are probably ahead of me by now. I'm content to leave the wiper as it is but I really would like to get the fuel gauge working. What do I need to do to make the gauges work properly with the newer tilt steering from the later model truck.? I don't recall there being any trouble hooking up the harness under the dash. But evidently there is a difference in the wiring of it.
Should I just try to find another tilt from a 70's truck or could I modify this one fairly easily?
Thanks



 
Icon Legend Permissions Topic Options
Report Post

Quote Post

Quick Reply

Print Topic

Email Topic

224 Views
FusionBB
FusionBB™ Version 2.1
©2003-2006 InteractivePHP, Inc.
Execution time: 0.079 seconds.   Total Queries: 17   Zlib Compression is on.
All times are (GMT -0800) Pacific. Current time is 11:09 PM
Top