GMC Repair: rear blower, yukon xl, haynes manual

Question
QUESTION: My 03 Yukon xl the rear ac blower stop working sometimes when I crank the engine start working  but is only 1 of 20 times

ANSWER: There is a resistor in the circuit that supplies power to that motor and it often is the problem when blowers work intermittently.  The one for the front blower is up inside the plastic cover on the passenger side kind of below the glove compartment.  The rear one should be somewhere near the rear blower motor, but it would be best to get a Haynes manual for your truck to find out just where it is and the procedure for getting to it.  It would be worth it to look in that direction because that is very often the problem with blower motors that work only sometimes.  Typically they will work less and less until they don't come on at all.  The resistor is about 120.00 or close at the popular parts shops.  Thanks for choosing me, and best of luck to you!

---------- FOLLOW-UP ----------

QUESTION: I just found out blower motor is good resistor is good but orange wire is getting only 4.5 volts

Answer
Is the orange wire coming off the resistor?  The wires coming off the resistor should be lower voltages than 12 except the one that turns it on high.  If you know the blower motor works and you know the resistor is good, but you are still not getting any power to the blower motor through the resistor, then check connections.  Often those plugs will get very hot and burn the contacts.  If all your plugs are good associated with the resistor, then you have nothing left except to look for a connection somewhere else.  Make sure the switch at the knob is good for sure, and the fuse.  Of course...check the fuse first :)