What is that little black blox that the battery plugs in to right in between the battery and radiator on an 87 trans am TPI? I rewired my electric fans to a toggle switch and now the car wont start. the fuel pump isnt turning on when I turn the key to accessory. I tested it by running a wire from the battery to the ALDL and the pump turned on. I stole the power from that little "black box" for my fans, and im wondering if this has anything to do with why it wont start?

 

The "little black box" is actually a single fuse holder. This is the fuse for the ECM memory and the fuel pump circuit.
Do NOT power the fans from this fuse since you will exceed the current rating for the fuse and the wires.

You must turn the key all the way to On to hear the fuel pump prime, Accessory is not enough, it only powers the radio.

And there is no need to run power straight to the fans, they both have relays to take care of switching the high-amp circuit. You just need to ground the relays to make the fans come on. Do a search here, there are plenty of people who are taking over the control of their cooling fans.

 

The fans stopped working and I had an overheat, so I just wired it to a switch so i could turn it on at will.

 

It is preferred and smarter to correct the electrical problem rather than bypass it. Now you must always remember to turn the fan on and off as the engine heats up and cools down. The ECM provides that functionality for you so that you can concentrate on driving, instead of flipping switches.

A nice article to help you troubleshoot and fix the cooling fan circuit:
http://www.austinthirdgen.org/index.php?pid=36

Hope this helps.
Lou

 

Do I need to turn it off while driving? Or can I just let it run and then turn it off when i stop?

 

Normally, the fans are not needed if the vehicle speed is above 42 mph (IIRC), which is what the ECM normally takes care of for you.

I would strongly recommend troubleshooting and fixing the cooling fan circuit because it will make it so much easier for you. I myself would hate to be driving around with a burning thought in the back of my head "what did I forget??" and then look down at my temp gauge and see it in the red and cook the engine.

 

My small block swap s10 is always running hot so I have a knack for always keeping an eye on the temp gauge haha, its kind of a nervous habit. My main problem right now is trying to get the car to run. Ive now been told that the black plug is just a fuel pump tester. What fuse in the block is for the FP?

 

There is no FP fuse in the fuse block. As I mentioned before, the fuel pump circuit is powered from that single-fuse holder by the battery. If you were told that it's a tester, that is incorrect information. If it has a red and orange wire and a slot for a standard blade fuse, that's your FP fuse.

 

What amperage of fuse is required?

 

20 amps, sir.

 

thank you sir. I hate electrical components. If i had my way every v8 would be carbed!