Wire Order for Jimmy Fuel Pump Connector? - S-10 Forum
S-10 Forum is the resource on GM S-series trucks, Suspension, engine information, Body Modifications, painting tutorials.  Modifications to suit every need, budget and whim

Wire Order for Jimmy Fuel Pump Connector?

Go Back   S-10 Forum > Specific Model Forums > 2nd Gen Forums > Blazer / Bravada / Jimmy / Envoy
New User? Register Forgot Password

LinkBack Thread Tools
Old 11-20-2010, 03:50 PM   #1
Registered User
Join Date: Jan 2009
Posts: 89
User is: OffLine
Wire Order for Jimmy Fuel Pump Connector?

I'm still trying to check the ground on my fuel pump wiring. I have the square, four-wire electrical connector unplugged from the top of the fuel pump assembly (tank is still in place). I've tried to pull back the harness plastic tubing but the wires are still coated with some dark gray covering. I cannot tell which wire is which.

The square connector has two contacts across the top and two across the bottom. I'd like to see a diagram of which is the gray 12V for the fuel pump, which is the fuel pump ground, which are for the sending unit.

I found this wiring diagram for a 2001 Jimmy, and it's helpful, but it doesn't help with figuring out the connector. The wires are F1 gray 12V for fuel pump, Black 1650 utility.

Sponsored Links
Old 11-22-2010, 02:02 AM   #2
Registered User
Join Date: Jan 2009
Posts: 89
User is: OffLine
Re: Wire Order for Jimmy Fuel Pump Connector?

Some progress... my 12 year old son was able to get his arms up to the connector so we could test the contacts. Here is what we got:

1998 Jimmy 4WD 4-door
Looking at the square plug, large clip to left

4.6V steady with key "Run"
Assume this is power to sending unit

10.6V for 2-3 seconds when key switched to "Run"
Assume this is power to fuel pump


We first checked each one independently with the voltmeter gauge grounded to the frame. Then we checked the TOP RIGHT grounded to each of the BOTTOM contacts and got the same voltage. So I believe this confirms my ground wires are good.

I don't know why I'm seeing 10.6V instead of 12V+. I should've checked the battery voltage but it was raining. The battery had run down and was on the charger for a few days.

If I could find the same male plug (anyone got an electrical plug number?) I would wire it to a full 12V and plug it into the pump.

I looked high and low under the hood and still cannot find the fuel pump test connector, supposedly coming off the harness near the ABS or by the center firewall. Some 2nd generation Jimmy's supposedly never got one; maybe this is one of those.

Anyway, I think my pump is bad. I've gone through all this because dropping the tank has become a nightmare. The front strap bolt and nut are solid rust. After a week of spraying with PB Blaster I finally got the nut to turn, but the strap is getting all twisted and bent. I'd like to cut the threaded rod a lot shorter to lose a bunch of the rusted portion, but I'm not crazy about showering the tank with sparks from a grinder. Maybe a Dremel and be careful with spark aim?
Old 11-22-2010, 02:49 AM   #3
i saw what you did there!
fast68chevy's Avatar
Age: 37
Join Date: Sep 2002
Posts: 3,571
Location: Lincoln IL
User is: OffLine
Re: Wire Order for Jimmy Fuel Pump Connector?

voltage drop in the FP wire

it happens and if its too much then the pump cant pump enough pressure or volume and will cause hard starts or no starts

ive had to repair this around 8 or 10 times on various trucks over the years by runing a new wire to replace the original

and purple wire is fuel level sender wire
Old 11-22-2010, 03:36 PM   #4
Registered User
Join Date: Jan 2009
Posts: 89
User is: OffLine
Re: Wire Order for Jimmy Fuel Pump Connector?


Ok then, I need to check the voltage at the battery. Then I should probably try to put a real 12V to the fuel pump to see if it runs.

Could low voltage cause the pump to not run at all? I don't think it's running at all. I suppose the combination of low voltage, fuel filter getting dirty and age could kill the pump. So another thing I may have to fix....

Thanks for the quick reply!
Old 11-22-2010, 08:11 PM   #5
Registered User
Join Date: Jan 2009
Posts: 89
User is: OffLine
Re: Wire Order for Jimmy Fuel Pump Connector?

found a pic that shows the wire colors.
thought i'd share it here.

Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the S-10 Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address.
Email Address:
How did you hear about us?
Enter a URL or Site name of who refered you to this site. (required. Only admins can see this)
Please enter your two letter state name to help other users and clubs find local users to them.(required)
Please select your insurance company (Optional)
Date of Birth
Your date of birth and age are displayed in several places on the forum. Only the administrator will have access to your date of birth should you choose to hide it via the privacy option below.
Month Day Year


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 01:13 PM.

Powered by vBulletin® Copyright ©2000 - 2011, Jelsoft Enterprises Ltd. SEO by vBSEO 3.2.0
vBulletin Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.