This has been a long term problem that has been a pain for about 6 months now.

i have a 99 blazer 4dr 4x4
103k mi

i was having problems w/ the alarm going off when it felt like when it rained / too humid.

about about 6 months ago it was having problems starting.
it would turn over but never start.
so i took it into a AAA auto shop and they could not find a problem w/ it
got it back and had the same problem later that day
got it towed in that time (rather than trying to jiggle a cable)
and they said that the fuel pump wasnt getting any power from the relay box under the hood.
so they went out to go figure out why and it was working again.
it never stopped working again (and i left it w/ them when i went on vacation for 2 weeks)
they installed a test light for me so i would know if it was getting power or not)

so since then it happens about once a month (when it rains)
i pop the hood and jiggle the cable that goes under the relay box (the left of the two bundles of cables going under the relay box when standing on left side of engine compartment)
then it will work after doing that 2-3 times (which makes me think that its a wire thats being pulled away from the underside of the relay box)

so i was digging in the hood tonight - pulled the air filter out to see if i could see anything better
and i noticed a wire w/ red coating and a washer / terminal attached to the end.

but its not connected to ANYTHING !?
i dont know if its supposed to be tension release for the cable bundle, ground cable, etc.

i tried touching it to the metal chassis that is below the relay box
touching it to nothing

initally the fuel pump wasnt getting any power (as per test light)
so i jiggled the cable and it started working again
then tested again if touching the red cable to ground / etc

no change.

see attached image (sorry about the quality - it was dark and i had a flashlight and my camera phone.

thanks for the help


[IMG]local://upfiles/8625/139B74778669456D85A623D7B5977B74.jpg[/IMG]

[IMG]local://upfiles/8625/EF951CAB8A374695A89F2581CB45A63B.jpg[/IMG]

 

Hey the wire should be mounted under that nut on the post in the picture. Here is an updated picture to help you out.

 

thanks for the info!

btw, you know what that wire / cable is?
is it a ground for one of the systems controled within the relay box?

any other suggestions for figuring out why "jiggling" the cable bundle for the fuel pump makes it work?
is there a way to check the individual cable's connection (i am assuming) under the relay box where it goes in?

thanks

 

bump

 

That wire is for the +12V for a 7 pin trailer hitch. It does not need to be connected to anything unless you have a 7 pin trailer plug.

Now, on your issues. Well, I would recommend you pull the relay box out and have a good look at the electrical contacts at the 3 large electrical connectors on the bottom of the box. You will also want to clean any and all terminals on the top as well as on the bottom of the relay box. With the bottom connectors, I would smear some dielectric grease over the connector before you put it back together. You will also want to make sure that all of the wires are still fully seated in the connectors before putting everything back together.

 

ok, i will have to give that a try this weekend.
it was working fine for a little bit, between the time i initially posted and now
but i went out this morning (got down to 28F last night) and i could not jiggle it into working this morning.

ill post back if i have any questions / thanks later.

thanks for the continued help.

 

well crap - i just typed in a ton of stuff and the browser hosed it...

anywho - i tried to remove the relay box and get to the underside (where the cables go in)

the understide has 5/6 sub-assembly boxes that are held onto the main relay box with hex-head screws which are inset 1/2" so i cant get at it (since i dont have any hex head / socket wrenches)

so my question is:

should i get a socket-wrench and open it up / clean the connector then apply dielectric grease to the connections?
since i would think that applying dielectric grease to to where the relay for the fuel pump connects (since i have tried using another relay (from the A/C & Horn) in the fuel pump relay location when it has failed to start in the past and not had any luck

i think this is a weather / temperature and consensation problem.
friday monring - it would not start in 28F weather
though this afternoon 65F it started up w/out a problem
and initially i was having problems w/ it starting in > 85/90F

i wonder if it is a condensation / metal thermal expansion / contraction issue on the relay, the relay connector, whatever is inside of the relay box, or the wire to the relay box?

thanks for any further help / aid

 

If you do not have a metric socket set yet, it's time to get one. You'll want to make sure that you have sockets down to 5 or 6 mm at the smallest. You can also disassemble this with a set of nut-drivers (screw drivers with a hex socket on the end).

If you find that you cannot get things clean enough or that the dielectric grease does not help, you may want to look into purchasing another fuse/relay box. Your best bet for that would either be eBay (s10warehouse) or your local junkyard.

From the sounds of it, something is corroded quite badly in/on your fuse box.

 

well i found one on ebay (not s10warehouse)
its $69 w/ $16 shipping

a lot better than the price the dealer quoted me - $300

i just wish i had as much knowledge about cars as i did about computers.
guess ill get a set of tools and see what i can see inside

once when i had taken it in to the dealer, i asked he if he could make an inline relay for the fuel pump - so i wouldnt have to spend the $300 on a new relay box.

here's to hoping that i can get my daily ride working again

 

so its been a while since i posted last - so please bear with me

my car has been working fine since I last posted
I got a socket set (sadly only down to 9mm) during black friday for $14

my car acted up for the first time (while driving) on tuesday
I was going to work after going to vote and it just DIED on me
I was going downhill and slightly breaking - my only guess was that i hit a bump (not a big one) and the light that i have installed on the dash went out
it happened AGAIN when I was going home and waiting @ a light - once again i was downhill, but stopped this time. (coincidence)

so i dug into the relay box hoping to figure-out what it was.
what i can determine (and i dont know much about cars - so i could be wrong) is the following

<top>
relay box plastic cover
relays that plug-in to relay matrix
relay box itself - [this looks like it is a closed box with female jacks on the top (for relays) and a distribution matrix in the sealed box with male pins on the bottom]
modular jacks - [four on the corners with a double sized module in the middle]
modules - [corner with 'fuel pump' relay in question was a 8x8 or 10x10 grid w/ screw in middle]
(modules consist of gird with plastic cap that goes on bottom)
<bottom>

I un-mounted the relay box from the chassis, disassembled the relay box, un-plugged the module I question. I looked @ the brown cable 'fuel pump' and noticed that its female jack was somewhat more bent than the other jacks in the matrix. so I attempted to bend it out a little (so it was more filling the gap and might get a better connection with the male pin from the relay box socket.) I then put a drop of dielectric grease into the top of the hole and pushed it down (so that it would not splooge out when i reconnected the module). I then reassmbled the entire setup.

I have only driven to work this morning - and did not have any problems - and hope not to.
Unless the problem lies WITHIN the 'relay box' itself (where i assume that there is a matrix that connects the relays (top) with the relay modules (below) and the power i assume that is what the matrix distribution in the middle of the 'relay box'

any suggestions?

thanks.