electrical problems in 1995 sierra 2500
 

my truck starts up fine and idles well. but when i turn on any electrical such as my lights, radio,brakes, and even putting it in reverse the truck will just die. i just fixed the shifter cable but im sure i didn't move anything. any ideas?

Was it doing that before the shift cable repair?

Just a guess, but simply from what you listed ,, when you add a load(lights,ect) the distributor maybe losing batt + circuit. Or if equiped, the PCM losing batt + or ground. check battery connections, alternator output.

it was not doing it before i changed the shifter.

i checked the cables and they are fine, the alternator is putting out 11.34.
one thing i remembered was i was in drive then it started to act like it was out of fuel and then it stalled. (it was at 1/8TH so i thought i ran out) i put more in and this problem came up.

thanks so much for replying

11.34 volts is not enough, adding a load such as lights, HVAC ect. will tax the charging sytem enought to effect the ignition voltage requirments. remember it's a 12volt system. Minimum DVM reading at idle should be 13.2V full load.

well i put a new alternator in and its still at 11.34. is there a computer that could cause the problem?

Get a voltmeter and check the hot stud behind the alt to see if you get a true 14.x volts. If you do then a worn out positive cable from the alt to the battery is most likely the culprit.

well i got the proper power now. but i still have the problem of it stalling under a load so i think its a ground or a short. is there a main ground other than the battery? or something that will tell me where all the grounding spots are

Just add some. I have added 3 grounds to my truck. One from the battery straight to the block, from the block to the firewall, and to the frame.

i have the exact same proble, did you ever get it fixed?

Yeh I got it fixed, added a bunch of new grounds, and added a new ground off the bat. Runs like a champ

it is probably the fuel pump the 7.4 has higher fuel pressure