Look at this pic......what is it and what is my truck missing.......

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

shinkle

Full Access Member
Joined
Apr 10, 2021
Posts
63
Reaction score
81
Location
AL
First Name
Barry
Truck Year
1987
Truck Model
R10
Engine Size
5.7
I'm still learning about these old trucks.....It looks like mine is missing some sort of relay on the left bracket near the passenger firewall.

Also what should the red wire hanging loose be connected to?

1987 R10 5.7l TBI

Thanks all.

You must be registered for see images attach
 

RoryH19

Full Access Member
Joined
Aug 21, 2015
Posts
1,668
Reaction score
1,082
Location
Texas
First Name
Rory
Truck Year
1987
Truck Model
R10 Silverado SWB
Engine Size
350 TBI
I'm still learning about these old trucks.....It looks like mine is missing some sort of relay on the left bracket near the passenger firewall.

Also what should the red wire hanging loose be connected to?

1987 R10 5.7l TBI

Thanks all.

You must be registered for see images attach

It's for the fuel injection, my 87 has the same only one.
 

gmbellew

Full Access Member
Joined
May 27, 2018
Posts
1,211
Reaction score
1,273
Location
Kansas city
First Name
glen
Truck Year
1990
Truck Model
suburban 1500
Engine Size
350
fuel pump relay
 

akchevrolet

Full Access Member
Joined
Sep 22, 2016
Posts
477
Reaction score
579
Location
Texas
First Name
Andrew
Truck Year
1987
Truck Model
R10
Engine Size
305
does that plug go to anything ive been wondering the same thing for mine haha
 

shinkle

Full Access Member
Joined
Apr 10, 2021
Posts
63
Reaction score
81
Location
AL
First Name
Barry
Truck Year
1987
Truck Model
R10
Engine Size
5.7
fuel pump relay

Am I missing a fuel pump relay? Wondering if it has anything to do with my passenger side tank not working.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,298
Reaction score
27,900
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
Most trucks don't have a second relay there. I don't remember off hand what would go there, if equipped.

The red wire is just a diagnostic hookup. Applying 12v there will energize the fuel pump.
 

jetmech

Junior Member
Joined
May 14, 2011
Posts
10
Reaction score
7
Location
Tx
First Name
Robert
Truck Year
1986
Truck Model
1500
Engine Size
350
The other bracket is for an identical relay that serves as a kickdown for TH-400 transmission. I have only seen this type of kickdown on computer controlled (TBI) trucks.
 

Craig 85

Full Access Member
Joined
Jan 25, 2017
Posts
3,913
Reaction score
4,112
Location
Nashville, TN
First Name
Craig
Truck Year
1985
Truck Model
K30 SRW
Engine Size
454/TH-400/NP205
I pulled this photo from a members 88-89 454 Suburban a few years back. It could be for the TH-400 or the factory aux fan relay. I added the aux fan to my K30, but in '85 this is the correct location.

You must be registered for see images attach
You must be registered for see images attach
 

akchevrolet

Full Access Member
Joined
Sep 22, 2016
Posts
477
Reaction score
579
Location
Texas
First Name
Andrew
Truck Year
1987
Truck Model
R10
Engine Size
305
I also have 2 relays there on my 87 hmmmm
 

gmbellew

Full Access Member
Joined
May 27, 2018
Posts
1,211
Reaction score
1,273
Location
Kansas city
First Name
glen
Truck Year
1990
Truck Model
suburban 1500
Engine Size
350
I have 1 relay there on my 90 350tbi suburban. it is the fuel pump relay.
 

Jawzjeep

Honk if parts fall off
Joined
Jun 5, 2021
Posts
476
Reaction score
941
Location
Washington
First Name
Joshua
Truck Year
1991
Truck Model
Suburban
Engine Size
350
91 sub with 700r4. Just agreeing. Only 1 relay. (Picture).

You must be registered for see images attach
My camaro I just sold had the same bracket that would hold two relays. They look like the same relays connection style and everything. On the Camaro there was two relays. One was for the fuel pump and the other was for the electric fans.
 

AuroraGirl

Full Access Member
Joined
Sep 8, 2019
Posts
9,674
Reaction score
6,829
Location
Northern Wisconsin
First Name
Taylor
Truck Year
1978, 1980
Truck Model
K10, K25
Engine Size
400(?), 350
If the vehicle was something like a big gm sedan, most likely a large rwd one in the dwindling days of the 80s, I could see a car maybe utilizing one of the relay spots for a WOT cutoff relay since that feature was becoming more common but this isn’t a very high likelihood, just an idea. The lockdown ajd fan experienced by others here make sense. I’d be curious if diesel trucks or cars of the time had the same bracket and if so what they held
 

Octane

Full Access Member
Joined
Dec 31, 2019
Posts
2,038
Reaction score
3,629
Location
Atlanta
First Name
Eddie
Truck Year
1977
Truck Model
K10
Engine Size
350
Most trucks don't have a second relay there. I don't remember off hand what would go there, if equipped.

The red wire is just a diagnostic hookup. Applying 12v there will energize the fuel pump.
I checked for a bad pump on my 90 chevy by turning the key on and putting a piece of hose into filler neck with other end put to my ear,I could hear pump running but I sure got a funny look from a passerby.lol
 

Raider L

Full Access Member
Joined
Sep 1, 2020
Posts
1,892
Reaction score
1,001
Location
Shreveport, LA
First Name
William
Truck Year
1974
Truck Model
C10
Engine Size
355
@Jawzjeep,

I see a little wire hanging from your relay to. What's it for? Is it like @bucket said, it's a test hookup? And TH400 in a TBI setup is for a kickdown relay?? That's weird.
 

Jawzjeep

Honk if parts fall off
Joined
Jun 5, 2021
Posts
476
Reaction score
941
Location
Washington
First Name
Joshua
Truck Year
1991
Truck Model
Suburban
Engine Size
350
@Jawzjeep,

I see a little wire hanging from your relay to. What's it for? Is it like @bucket said, it's a test hookup? And TH400 in a TBI setup is for a kickdown relay?? That's weird.

I can't speak for the kick down relay. Somebody else will have to. I just snapped a pic of the bracket since it only had 1 relay on mine.

I dont know what the wire is for. If bucket said its a test hookup it probably is. Ive never tried it.
 

Latest posts

Forum statistics

Threads
43,938
Posts
946,058
Members
35,982
Latest member
jake26104
Top