stalls with brakes or headlights

After having alternator tested and replacing after seeing voltage spikes with loads on the vehicle still stalls with the brakes or headlights on...after disconnecting the switch for the headlights it stayed running with the brakes on, does this mean it is the headlight switch?? Could the ignition switch cause these symptoms or a short/bad ground somewhere else? Thank you in advance!!


sorry, its 97 4wd ls with the 4.3 liter motor with 105k miles. No the new alternator hasn't been tested because I am afraid to drive it n e where. Will do though, I guess that makes sense!! Thank you MT-2500!

Welcome to AF.
We need.
Year engine and mileage what model?
Has the new alternator and charging system been tested?

thank you

After having alternator tested and replacing after seeing voltage spikes with loads on the vehicle still stalls with the brakes or headlights on...after disconnecting the switch for the headlights it stayed running with the brakes on, does this mean it is the headlight switch?? Could the ignition switch cause these symptoms or a short/bad ground somewhere else? Thank you in advance!!


sorry, its 97 4wd ls with the 4.3 liter motor with 105k miles. No the new alternator hasn't been tested because I am afraid to drive it n e where. Will do though, I guess that makes sense!! Thank you MT-2500!


You are welcome.
A 97 is also a bad year for ign switches.
Good luck
And let us know how it goes.

My bud seems to think all those wires headlights and brakes run through the turn signal on the column...Now if I can get him to check it 4 me that would be great!! let u all know how it turns out!!

oh I am now somewhat convinced its an ignition switch including the key cylinder cause 4 years ago i had this one replaced and sometime i couldn't get the key out cause the cylinder wouldn't turn all the way off...anyway that problem was so far out of my mind till the blazer died while accelerating onto a highway today. After calling 4 a tow, i found the interior lights not working when the door opened and I couldn't even shift it out of park!!

the key thing seems to be a different thing with a wire in the shifter according to another topic i saw!! The manual i saw actually says to check for proper operation of the wire in the shifter!

ummm well yes 97 is a bad year for ignition switches...I told the mechanic just to change it, he didn't and now having problems again, just going to switch the ignition Module....proper name?

ummm well yes 97 is a bad year for ignition switches...I told the mechanic just to change it, he didn't and now having problems again, just going to switch the ignition Module....proper name?

Needs some proper testing.
Good luck