Have you checked the security system ? Could be a bad chip in the key.
Or the neutral safety switch, or a bad connection between the key switch and the starter.
How slow?There is a low speed fan relay and a high speed fan relay over above the battery in the fuse box.Pop the high speed fan relay cover off and manually push the contacts together as a check that the fans can run fast.May just be a bad ground.
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No B+ power at the PWR SLDG DR circuit breaker . Where does the power come from for the circuit breaker ? You have to look at a electrical distribution diagram . Plus there are other power supply's to the power door module . IGN 1 fuse 10 - hot when key is in run or start , plus radio fuse - 10amp . underhood fuse box . The sliding door circuit breaker gets B+ from BATT MAIN 2 fuse 60amp location under hood fuse / relay box .
I don't know if you can get at it from engine compartment? On some vehicles, I safely raise and support the vehicle, then remove passenger side tire to see if it is easier to get at? It just depends on what is the easiest for you? Note, when working under a vehicle there are safety issues, safety is your responsibility.
Could be a few thing's . Hooking up a scan tool an checking for DTC'S - diagnostic trouble codes would be the first thing to do., viewing speed input data to the PCM - engine computer from the VSS - vehicle speed sensor . Also if the PCM see's this input it outputs this info on the class 2 serial data communication network to the instrument cluster . The instrument cluster has a microprocessor with logic programmed into it , an controls a electric motor to set the speedometer needle . GM had bad Stepper motors in their instrument clusters from 2003 to 2006 .
Does the vehicle shift ok , no running problems ? Any light's lit on the instrument cluster ? check engine etc....
How to repair GM Instrument Cluster Speedometer Gauge Stepper
,i can only think of one thing short in the wire somewhere, ?????
WRONG - open wire not shorted . Looking at wiring diagrams an using a DVOM - digital volt ohm meter to test the starter electrical circuits is the proper way to diagnose . Plus knowing how the circuit works would help . Your going at this blind.... That's why professional technicians go to training classes an why the factory spends millions on publishing service repair manuals . Looking at a wiring diagram i see that when the key is turned to the start position it sends a voltage signal to the PCM - engine control module . The PCM then supply's a ground to energize the starter relay ,this will close the contacts inside the relay sending B+ voltage to the S terminal on the starter solenoid . I see the PCM/CRANK fuse 10amp. located in the I/P fuse box. PCM/ABS fuse 10amp. I/P fuse box . I also see fusible link C (gray) this comes from the starter main batt. cable hook up. Do you know how a relay works ?
VEHICLE RELAYS Operation Diagnosis
Having a factory or professional grade scan tool to check input from the ignition switch to the PCM an checking starter relay control would be a big plus in the diagnostic procedure . But can diagnose without it. Does your vehicle have a security light lit on the instrument cluster ? If so , this will keep the PCM from starting the vehicle . Free wiring diagrams here http://www.bbbind.com/free-tsb Enter vehicle info. year , make , model an engine size. under system click on engine , then under subsystem click starting . Click the search button then the blue link.
Electric Testing Techniques You Need to Know
Could be any number of electronic sensors ,engine management systems componets etc..... Having a professional repair shop hook up a factory or professional scanner to view engine sensor data parameters is what you should do .
064 Emission Tests Scan Data Pre Check002 Fuel System Tests Start Here
Without testing we'd only be guessing . You wouldn't want to replace a bunch of parts you don't need ,would you ?
https://s2.postimg.org/einm75w6x/power_windows.jpg
Click on the link.
Check the wire harness on hinge side of driver door. Probably has a protective rubber boot, see if you can pull boot back far enough to get at yellow wire, key on, use a test lite and probe yellow wire, see if there is voltage.
At the lower part of diagram, see black wire, terminal G, that is ground, find that in wire harness and check it. You can use a test lite connected to battery voltage, probe the black wire, if the lite comes on, at least the ground is good enough to turn on the test lite. Because you open and close the driver door so much, sometimes those wires break.
When probing any wires, cover the hole with fingernail polish or something, when your done.
Free wiring diagrams here http://www.bbbind.com/free_tsb.html
Enter vehicle info. under system click body & accessories , then under subsystem click on wiper/washer.Then click search button ,then blue link !
I'd probably safely raise and support the rear of vehicle, make sure rear wheels turn freely, no braking action unless brakes are applied. You could raise one wheel at a time.
Check the emergency brake release mechanism, the switch and wiring circuit?
My main concern is your not driving down the road with braking action ongoing w/o brakes being applied.
My ex drove 50 miles one time with e-brake not fully released, the brakes were smoking like crazy when she got home. Glad she got home ok. I'm glad it didn't catch fire.
