1996 Jimmy - No Electrical Power - Head Gasket R&R

I just removed and replaced the head gaskets for my 1996 Jimmy and everything is back together. I have no power not even enough to light the interior light or radio. Anyone know what it could be. Someone said mass air flow sensor may not be in all the way - battery and cable are good. Please HELP! Thanks!!

i have the same problem, I just replaced the head gasketts in my 1995 jimmy and now no power at all. there is power from the battery to the starter,alternatorand the box with all the brake lines going into it but there is nop power to the fuse box no headlights nothing. let me know what ya find out if anything!

Try to remember how you disassembled it... No power=a cable off somewhere

Are the battery cables properly routed and tight?
Did you attach the grounds to the back of the heads?

yea the power cables are all hooked up. the only thing I can think of is maybe a wire got pulled loose somewhere when reinstalling all the clips. the 4 grounds on the back of the heads are hooked up bolted tight and i made sure the heads and block ect is all grounded. I just dont get why there is no power at all. is there maybe a main fuse or breaker that will cut all the power? dome lights head lights even the light under the hood is out. on another car i had everything unhooked and hit the power cable on the battery and got dome lights and headlights..

it will be fun checking every fuseable link....what a pain!

one more question...
what color wire goes on the back of the alternater is it the one straight from the battery or the green one from the starter? or is the green one a ground it reads no power but someone said the alternator does not go straight to the battery the green one is red b4 the fuseable link but i have no idea where it goes.

yea the power cables are all hooked up. the only thing I can think of is maybe a wire got pulled loose somewhere when reinstalling all the clips. the 4 grounds on the back of the heads are hooked up bolted tight and i made sure the heads and block ect is all grounded. I just dont get why there is no power at all. is there maybe a main fuse or breaker that will cut all the power? dome lights head lights even the light under the hood is out. on another car i had everything unhooked and hit the power cable on the battery and got dome lights and headlights..


HI, I POSTED ORIGINAL QUESTION. ANY LUCK YET? I LOOKED AT ELECTRIC DRAWING FROM REPAIR MANUAL AND ALL THAT I COULD SEE IS THAT THE MANUAL OR AUTOMATIC DRIVE COULD LOCK OUT ALL POWER BUT NOTHING ELSE. MY SON IS ASKING A GM MECHANIC AND MAYBE WE WILL HAVE AN ANSWER SOON. THANKS FOR FOLLOWING UP ON THIS!!

Try to remember how you disassembled it... No power=a cable off somewhere

From you posts, it looks like you know your vehicles. What cable would prevent any power to the vehicle. Not connecting a sensor does not seem critical. Thanks for your reply.

Are the battery cables properly routed and tight?
Did you attach the grounds to the back of the heads?

GM Merlin

I found this post you did a couple years back. I could not find the fuse but this seems possible. here is your quote and THANKS!!

I'm taking this info off a 98 model, but I think the 97 is the same.
Check and see if you have 12 volts at the battery stud on the underhood electrical center.
If not, check the 175a mega fuse which is located on the radiator support near or below the battery.
This fuse powers everything except the starter and alternator.

__________________
Why do you never have enough time or money to do the job right the first time, but enough time and money to do it again?

Well I think it's all figured out. the dealer told me that if i had unhooked anything b4 disconnecting the battery that the brain box is probablly toast. so I have to pay him 65 bucks to hook it up to the computer and if its not that he will tell me what it is. I dont think i unhooked anything b4 disconnecting the battery cables but for 65 bucks what the heck,at least i'll know for sure. He did say that that is most likly what happend because its unusuall to have no power anywhere but the 3 leads comming off the battery.

Well I think it's all figured out. the dealer told me that if i had unhooked anything b4 disconnecting the battery that the brain box is probablly toast. so I have to pay him 65 bucks to hook it up to the computer and if its not that he will tell me what it is. I dont think i unhooked anything b4 disconnecting the battery cables but for 65 bucks what the heck,at least i'll know for sure. He did say that that is most likly what happend because its unusuall to have no power anywhere but the 3 leads comming off the battery.


Thanks! Let me know what you find out. My son said he disconnect the battery first also but does not remember if he install battery before connecting all sensors. Thanks again for replies!!

Well I think it's all figured out. the dealer told me that if i had unhooked anything b4 disconnecting the battery that the brain box is probablly toast. so I have to pay him 65 bucks to hook it up to the computer and if its not that he will tell me what it is. I dont think i unhooked anything b4 disconnecting the battery cables but for 65 bucks what the heck,at least i'll know for sure. He did say that that is most likly what happend because its unusuall to have no power anywhere but the 3 leads comming off the battery.


When do you take it in? Any LUCK?? Thanks!!

Thanks! Let me know what you find out. My son said he disconnect the battery first also but does not remember if he install battery before connecting all sensors. Thanks again for replies!!

Did you find out if it was your brain box that caused the problem? thanks!

Well I think it's all figured out. the dealer told me that if i had unhooked anything b4 disconnecting the battery that the brain box is probablly toast. so I have to pay him 65 bucks to hook it up to the computer and if its not that he will tell me what it is. I dont think i unhooked anything b4 disconnecting the battery cables but for 65 bucks what the heck,at least i'll know for sure. He did say that that is most likly what happend because its unusuall to have no power anywhere but the 3 leads comming off the battery.


Did you fix your power problem yet - was it the brain box? Thanks!

Well I think it's all figured out. the dealer told me that if i had unhooked anything b4 disconnecting the battery that the brain box is probablly toast. so I have to pay him 65 bucks to hook it up to the computer and if its not that he will tell me what it is. I dont think i unhooked anything b4 disconnecting the battery cables but for 65 bucks what the heck,at least i'll know for sure. He did say that that is most likly what happend because its unusuall to have no power anywhere but the 3 leads comming off the battery.

Hey, It is the green wire at the alternator that is not homed correctly which gave no power at all!!!

I am taking it in this weekend I should know by next week sometime, and if all goes well i will be driving it next week sometime!....Just a word of advice ... if you ever have rough idle or really poor gas milage after checking all the obvious things take the intake apart and check there. On mine someone had used silicone on the cpi unit when it started leaking (wich is common on these when they have higher milage) and the nut kit(the send and return lines inside the intake) was leaking also... Im thinking this may have something to do with the bent pushrod i found when changing the head gasketts but im not sure what caused that.. well anyway i'll keep ya posted.

Did you fix your power problem yet - was it the brain box? Thanks!


Did you solve your problem? Thanks!

Nope not the brain box.. The dealer was not very detailed the paper says pushed inside no power to anything checked battery ok connected some wires got it to crank. some wires being? thats what id like to know!.. the only wire i saw was a green one that goes to the back of the alternator right with the power wire from the battery .. we had the green one grounded to the alternator... maybe that was it but i dont know for sure. once i hook up my scanner i will post the actuall invoice.all i can say is make sure every wire is hooked up because just one off can mess it all up..

Hey 12field i was just reading through these posts and saw yours about the alternator was that green wire your problem also?