Looking for its mate
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 897
Likes: 12
From: Land of Whiskey Rebels, PA
Looking for its mate
The patient: '90 L98
Said patient has a single, red wire, about 1-1/2 inches long, with a black plug, hanging out of the wiring harness next to the firewall, driver's side. It is located in front of the brake booster and under the master cylinder. It is not long enough to reach anywhere or anything. I have looked for its mate, if it has one, without success.
Any advice would be appreciated.
Mike
Said patient has a single, red wire, about 1-1/2 inches long, with a black plug, hanging out of the wiring harness next to the firewall, driver's side. It is located in front of the brake booster and under the master cylinder. It is not long enough to reach anywhere or anything. I have looked for its mate, if it has one, without success.
Any advice would be appreciated.
Mike
Last edited by j-wireman; Feb 9, 2007 at 09:27 AM.
Racer
Joined: Nov 2006
Posts: 301
Likes: 0
From: Ft. Worth Texas
Just went to the car and i dont see a single red wire loose around the batt. can you post a pic.
Steve
Was cleaning under the hood yesterday and found that wire you are talking about
has spade terminal on end not hooked to anything is comes that way. now i will hace to go get my wire manual and see if its in there!
Steve
Steve
Was cleaning under the hood yesterday and found that wire you are talking about
has spade terminal on end not hooked to anything is comes that way. now i will hace to go get my wire manual and see if its in there!
Steve
Last edited by Bulldog Steve; Feb 18, 2007 at 12:16 PM.
Burning Brakes
Joined: May 2006
Posts: 904
Likes: 0
From: Boynton Beach FL
The patient: '90 L98
Said patient has a single, red wire, about 1-1/2 inches long, with a black plug, hanging out of the wiring harness next to the firewall, driver's side. It is located in front of the brake booster and under the master cylinder. It is not long enough to reach anywhere or anything. I have looked for its mate, if it has one, without success.
Any advice would be appreciated.
Mike
Said patient has a single, red wire, about 1-1/2 inches long, with a black plug, hanging out of the wiring harness next to the firewall, driver's side. It is located in front of the brake booster and under the master cylinder. It is not long enough to reach anywhere or anything. I have looked for its mate, if it has one, without success.
Any advice would be appreciated.
Mike
(I do this all the time when I sell my cars, I never remove the wiring, just the 'good' bits of equipment
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
red wire
When I bought my 86, there was a red wire that was dyked off and the
previous owner said it was for the phone. Remember those phones that looked like a small laptop? that's what was installed under the driver's seat in my car, with the handset in the console.
just my 2c
Chris
previous owner said it was for the phone. Remember those phones that looked like a small laptop? that's what was installed under the driver's seat in my car, with the handset in the console.
just my 2c
Chris
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 897
Likes: 12
From: Land of Whiskey Rebels, PA
Thanks for your replies, gentlemen.
No, it is a small wire (18-20 Gauge ?) with a plug that might fit on a flat blade on a sensor or something. It comes out of the large harness where the smaller harness branches off. The fact that it is only about 1-1/2 inches long and isn't long enough to reach anything just baffles the s**t out of me.
Sorry, Steve, I can't post a picture. The best I can do is MAIL you a 35 MM photo. Post pictures on the internet? Hell, I can't even get my printer to work anymore.
OH WAIT!!! My seat belt and air bag lights are on. Could this wire, possibly, connect to the sensor under the battery box?? (I don't know. I'm clutching for straws at this point.)
Mike
No, it is a small wire (18-20 Gauge ?) with a plug that might fit on a flat blade on a sensor or something. It comes out of the large harness where the smaller harness branches off. The fact that it is only about 1-1/2 inches long and isn't long enough to reach anything just baffles the s**t out of me.
Sorry, Steve, I can't post a picture. The best I can do is MAIL you a 35 MM photo. Post pictures on the internet? Hell, I can't even get my printer to work anymore.
OH WAIT!!! My seat belt and air bag lights are on. Could this wire, possibly, connect to the sensor under the battery box?? (I don't know. I'm clutching for straws at this point.)
Mike
Last edited by j-wireman; Feb 9, 2007 at 10:33 PM.
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Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
I know of this wire you describe. My 86 has a single red wire ~2" or so long with a connector just under and to the right of the battery. It's not connected to anything on mine. I don't have the seat belt light on and mine didn't come with airbags.
If you would like, I an take a pic later this evening.
If you would like, I an take a pic later this evening.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
If I remember this correctly, GM used this as a means of testing the fuel pump - but I can't remember when they dropped it and added it to the Diagnostic Link. On my '89, the splice - with a Barrel Plug - is connected to the ECM memory circuit. Easy way to erase everything. See what's hanging out of your ECM - isn't it mounted above the battery or is it on the other side?
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
It's called the Fuel Pump Prime Connector.
It's a fused 12 volts used for testing.
An example of its use on the C4's 84-89. If you jumped it to pin G of the Diag. Connector, it would apply 12 volts to the fuel pump relay contact which then provided 12 volts to the fuel pump fuse then 12 volts the fuel pump.
It's a fused 12 volts used for testing.
An example of its use on the C4's 84-89. If you jumped it to pin G of the Diag. Connector, it would apply 12 volts to the fuel pump relay contact which then provided 12 volts to the fuel pump fuse then 12 volts the fuel pump.
Last edited by Hooked on Vettes; Feb 9, 2007 at 01:32 PM.
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 897
Likes: 12
From: Land of Whiskey Rebels, PA
Oh, no, no, no. I know what wire (with the barrel plug) you're talking about (it's under the battery). That wire is OK. That's not the wire I was asking about.
The ECM is located above the battery. Everything is where it should be. It's just that that little red wire hanging out of the harness is bothering me--as if it should be connected to something. In my trade (electrician), if we pull a spare wire or cable, we label it so the next guy knows what it is, where it came from, and/or where it's going. I couldn't imagine GM "pulling a spare", as that adds cost and weight. So, I had to assume that it was supposed to be plugged into/attached to/ connected to something. But it is so short, it doesn't reach anything. Maybe it IS for testing the fuel pump.
Check back, 'SunCr', when 'RRT vette' posts the picture. We'll figure it out, then.
Mike
The ECM is located above the battery. Everything is where it should be. It's just that that little red wire hanging out of the harness is bothering me--as if it should be connected to something. In my trade (electrician), if we pull a spare wire or cable, we label it so the next guy knows what it is, where it came from, and/or where it's going. I couldn't imagine GM "pulling a spare", as that adds cost and weight. So, I had to assume that it was supposed to be plugged into/attached to/ connected to something. But it is so short, it doesn't reach anything. Maybe it IS for testing the fuel pump.
Check back, 'SunCr', when 'RRT vette' posts the picture. We'll figure it out, then.
Mike
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
What??? I haven't owned a home yet with a marked Service Panel!
My fuel pump test circuit runs to Terminal G at the Diagnostic Link - there's nothing dangling in the Engine Compartment and the only wire to nowhere is at the fuel pump (even though not produced, the '89 was wired for the ZR1 and I can't help but wonder if yours isn't some feed to the secondary pump relay which is used on that model). Since you have a Seatbelt and Air Bag light, I'd try diagnostics (I'm assuming there's a CCM or Body Computer). I thought the procedure was in Tech Tips, but I couldn't find it, so maybe someone can post how you get those CCM Codes.
My fuel pump test circuit runs to Terminal G at the Diagnostic Link - there's nothing dangling in the Engine Compartment and the only wire to nowhere is at the fuel pump (even though not produced, the '89 was wired for the ZR1 and I can't help but wonder if yours isn't some feed to the secondary pump relay which is used on that model). Since you have a Seatbelt and Air Bag light, I'd try diagnostics (I'm assuming there's a CCM or Body Computer). I thought the procedure was in Tech Tips, but I couldn't find it, so maybe someone can post how you get those CCM Codes.
Pro
Joined: Apr 2005
Posts: 590
Likes: 0
From: Boynton Beach, FL
Test the red wire with the ignition off. There should be 0V. It is for powering fuel pump with engine off. You measured 12V because you measured voltage with engine running, i.e., voltage to pump. Apply 12V with engine off and you should hear pump run.
Larry
Larry
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
The schematic I posted is for a 90 which is the year the original poster is asking about.
On a 90 the Diag. connector Pin G is grounded to pull DTC's. DTC's for the PCM, CCM and Active Suspension are then displayed on the Dash Cluster.
I looked at the Helms schematic for a 89 after SunCr mentioned he had no Red wire hanging in the Battery area. He's correct. So I'd assume 84-89's did not have this 12 volt connector going to no where.
On a 90 the wire was most likey used by the service people on the assembly line. The wire provides 12 volts and is protected by a fusible link as long as the Fuel Pump Relay is not energized.
Last edited by Hooked on Vettes; Feb 9, 2007 at 05:33 PM.
Thread Starter
Burning Brakes
Joined: Nov 2004
Posts: 897
Likes: 12
From: Land of Whiskey Rebels, PA
Gentlemen, thank you for all of your research in trying to solve my "mystery".
I put my VOM (Volt-Ohm-Meter) between the red and ground and here is what I came up with: Red wire is NOT hot (energized), a) with ignition on, b) with car running, or, c) with ignition off. However, said wire IS hot immediately after turning ignition off and for about five seconds afterward, about the amount of time I can hear the fuel pump run before it shuts off. So, it is definitely connected to the fuel pump circuit, as some of you fine gentlemen had speculated.
GOOD JOB, MEN
Well, SunCr, obviously, I didn't wire your house. If I had, every cable and conductor would have been run straight, vertically and horizontally, in a "neat and workmanlike manner". All circuit terminations would have labels. That's the way I do it. However, numerical labelling of circuits is not required by the National Electrical Code (but, it should be). The N.E.C. does not define the term "..in a neat and workmanlike manner." I have been fired/laid off more than once for refusing to do a half-assed job. And, by God, I'll do it again, if the opportunity presents itself.
Thank you, again, Gentlemen.
Mike
'90 'vert
I put my VOM (Volt-Ohm-Meter) between the red and ground and here is what I came up with: Red wire is NOT hot (energized), a) with ignition on, b) with car running, or, c) with ignition off. However, said wire IS hot immediately after turning ignition off and for about five seconds afterward, about the amount of time I can hear the fuel pump run before it shuts off. So, it is definitely connected to the fuel pump circuit, as some of you fine gentlemen had speculated.
GOOD JOB, MEN
Well, SunCr, obviously, I didn't wire your house. If I had, every cable and conductor would have been run straight, vertically and horizontally, in a "neat and workmanlike manner". All circuit terminations would have labels. That's the way I do it. However, numerical labelling of circuits is not required by the National Electrical Code (but, it should be). The N.E.C. does not define the term "..in a neat and workmanlike manner." I have been fired/laid off more than once for refusing to do a half-assed job. And, by God, I'll do it again, if the opportunity presents itself.
Thank you, again, Gentlemen.
Mike
'90 'vert
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
wire
how long does the burnoff circuit work for?
could it be possible to have a burnoff power wire to test that circuit and energize the fuel pump at the same time?
the wire looks like there's TWO red wires coming out of the fusuble link side.
could it be possible to have a burnoff power wire to test that circuit and energize the fuel pump at the same time?
the wire looks like there's TWO red wires coming out of the fusuble link side.