OK, HERE IS THE PROBLEM....

I OWN A 1987 TRANS AM 5.0 T.P.I 305 STOCK.
WHEN I TURN ON MY HEAD LIGHTS THE TWO LITTLE GREEN LEFT AND RIGHT TURN SIGNAL INDICATORS LIGHT UP UNTIL I SHUT OFF MY HEAD LIGHTS (REALLY ANNOYING)
SECONDLY.. AND THIS IS THE WEIRD ONE, WHEN I SHUT MY CAR OFF I HEAR A HUMMING COMING FROM THE REAR OF MY CAR, MY BEST GUESS IS THAT SOME HOW MY FUEL PUMP IS STILL CYCLING ON AND OFF TILL MY BATTERY IS DEAD. ANY IDEAS????

 

Howdy,

it would help if you could locate the Caps Lock button and turn it off. Capital letters on the Internet imply loud voice.

Anyway, problem 1: do the turn signals outside the car also light up with the headlights? Do the turn signals work with/without the headlights?

Problem 2: our engines have a backup fuel pump switch. On the 1987 V8 blocks, it's right by the oil pressure sender on top back of the block (driver side). It should have an orange and tan/white wire. If this fuel pump switch (based on oil pressure) goes bad, it will keep the fuel pump running all the time. Try disconnecting it. If it helps, the switch is bad.
Also, it might be the fuel pump relay sticking. You can find it on the driver side firewall, in the corner, by the brake booster. There will be multiple relays there. It's the one that has, again, an orange wire and a tan/white wire. Try disconnecting it. If it helps, the relay is bad.

Hope this helps.
Lou

 

I had a similar problem with my lights when i bought my 83 trans am . When i stepped on the brake pedal the turn signals would also light up, this drove me crazy looking for a short or bad ground. I worked on this thing for weeks tracing wires all over the car, finally took it to an auto electric shop,they had it for two weeks. Turned out the problem was the previous owner installed the wrong tail light bulbs. I forget if he put in the double contact point bulbs or what but it was as simple as replacing the bulbs and paying the shop $272.00. To make a long story short check for the correct bulbs.

 

The humming might be coming from a one way air vent that allows air into the fuel tank if the vacuum exceeds a certain amount. To test this, when you shut off your car and hear the humming, jump out and open your gas cap. That will allow lots of air into the gas tank. If the humming stops then I would assume the humming was from the one way valve. It is located on the outside of your fuel tank, in front of the fuel tank. It is plastic and hangs down from a rubber hose. If you crawl under the car and look between the fuel tank and the back of the rear seat panel you will see it. Normally it has a little bracket it rests in.

If you turn off your engine and wait about 10 seconds then turn your ignition key ONLY to the ON (RUN) position you can hear your fuel pump run for about 2 seconds. That will let you know what it sounds like so that you can compare the sound to what you are hearing from the back end.

 

Turn signal indicator lights on due to a bad ground up front in your lighting circuit. Headlights searching for a ground, return through the dash indicators and light them up either bright or most times dimly. Use a jumper wire to a good ground and connect to each headlight ground - I bet that problem will go away when you find which one has the bad ground.
Corky

 

your turn signal lights comming on with the headlights indacates a bad exterior bulb.