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Gary
Gary, Chevy Technician
Category: Chevy
Satisfied Customers: 15894
Experience:  15 years GM master tech
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01 chevy impala no crank no start. no signal at crank fuse.

Customer Question

01 chevy impala no crank no start. no signal at crank fuse. have by passed security with yellow and black wires. still no power at starter.
Submitted: 1 year ago.
Category: Chevy
Expert:  Gary replied 1 year ago.

the pcm crank fuse in the left inside fuse box that 10 amp fuse does NOT show 12 volts at it when you hold the key to crank position ?

Customer: replied 1 year ago.
nothing at all. have changed ignition switch and key tumbler,checked all fuses& relays,bcm conections.
Expert:  Gary replied 1 year ago.

I that fuse will NOT show 12 volts when holding the key to crank at the ignition switch when the key is held to crank does the yellow wire show 12 volts at it testing with all the connectors plugged in ?

also does the red at that connector show 12 volts all the time ?

Expert:  Gary replied 1 year ago.

* if *

Customer: replied 1 year ago.
have to check, if it isn't what's my next step.
Customer: replied 1 year ago.
How long do I have to ask questions.
Expert:  Gary replied 1 year ago.

if it is showing 12 volts on the yellow when you hold the key to crank and that fuse shoes NO volts then that yellow wire between the switch and fuse box is bad or where it connects to the back of that fuse box

if the yellow shows NO volts and the red shows 12 volts then the switch or terminals in the switch connector are bad

if the red wire shows NO volts and the big fuse in the under hood fuse box called IGN SWITCH is good and shows 12 volts at that fuse then the red wire from the switch to the under hood fuse box is bad

Expert:  Gary replied 1 year ago.

this post has no time limit

you can always get me back through this post for FREE with any follow up anytime with this question even after you rate us here at Justanswer !

Customer: replied 1 year ago.
There is power under hood at that fuse. I will check the rest later, I'm done for the night. thank you.
Expert:  Gary replied 1 year ago.

ok let me know

Customer: replied 1 year ago.
which yellow wire are you talking about? there is a lot of yellow wires under the dash. If your talking about the yellow wire at the ing switch it blows AUX fuse when tested.
Expert:  Gary replied 1 year ago.

terminal B in the picture of the connector for the ignition switch

back probing that wire terminal from behind when holding the key to crank that yellow wire should show 12 volts

there is only one yellow wire at that connector i showed you at the ignition switch

Expert:  Gary replied 1 year ago.

here it is again for you

Customer: replied 1 year ago.
12 volts at ing switch & fuse box. yellow & red.
Expert:  Gary replied 1 year ago.

so the yellow wire only shows 12 volts when you hold the key to crank position and the fuse crank still will not show 12 volts when you hold the key to crank ?

Customer: replied 1 year ago.
Both show more than 12 volts, when check power at fuse nothing.
Expert:  Gary replied 1 year ago.

ok im just being sure the yellow at the switch will ONLY show 12 volts when holding the key to crank ?

i just need to know for sure am i am sorry for asking again

Customer: replied 1 year ago.
A little more than 12.
Expert:  Gary replied 1 year ago.

ok great thank you

so this now comes down to that yellow wire from the ignition switch to the fuse box that has the crank fuse

you need to get to the back of the fuse box and get to this connector here C1

you need to see if the yellow wire in terminal # ***** shows 12 volts when you hold the key to crank

if it does then the terminal in that connector is bad or there is a bad connection in the back of the fuse box of the fuse box is bad

if the yellow the yellow does NOT show 12 volts when you hold the key to crank at that fuse box terminal but it shows 12 volts at the ignition switch when you hold the key to crank then the yellow wire is bad and its best to just run a new one from the ignition switch to the back of the fuse box terminal # *****

Customer: replied 1 year ago.
The yellow crank wire at the back of fuse box does show 12 volts
Expert:  Gary replied 1 year ago.

ok then either the terminal in the back of the fuse box or the terminal in the connector is bad or not making a good connection or the fuse itself is not making a good connection in the box or the fuse box is bad internally

you have your problem narrowed down to that

Customer: replied 1 year ago.
Replaced fuse cleaned contacts, before replacing fuse box. how can I check transaxle to make sure that's not stopping my crank signal to starter?
Expert:  Gary replied 1 year ago.

if anything under the hood and or the transaxle was causing this issue you WOULD show 12 volts at that fuse when holding the key to CRANK position

the power is not making it to the fuse inside so it is not making it out under the hood to the transaxle

Expert:  Gary replied 1 year ago.

how are you making out ?