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kevin, Ford Mechanic
Category: Ford
Satisfied Customers: 350
Experience:  7 years
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1997 F150 4x4 light will not come and 4x4 does not work

Resolved Question:

1997 F150 4x4 light will not come and 4x4 does not work
Submitted: 6 years ago.
Category: Ford
Expert:  kevin replied 6 years ago.
There is a contact switch mounted on the transfer case next to the shift linkage, this switch is activated when the shifter is in 4x4, once the switch is activated it sends a electrical signal to a vacuum selonoid on the firewall that controls the vacuum sent to the front diff to engage the shift fork inside the diff, if this switch is bad then the transfer case will engage but the 4x4 light wont come on and the vacuum selonoid wont engage the front diff, first check for a loose or failed/corroded connection at the sensor on the transfer case
Customer: replied 6 years ago.

we have looked at the connections on the transfer case,

? where is the switch two prong switch right? - already looked at

Expert:  kevin replied 6 years ago.
Yes, the other possible cause if the switch is good can be the generic electronics module, this controls 4x4 operation to the front diff lock up collar, I recommend to first remove the switch and inspect, if it checks out then you will need to have the GEM module scanned for codes to determine the problem
Customer: replied 6 years ago.

i have no voltage at the switch, should there be voltage or is it a ground system/


Generic electronic module is it used on manual shift transfercases?


Expert:  kevin replied 6 years ago.
The GEM is used on mechanical shift on the fly 4x4 systems, There should be ground on the grey wire off the switch, you can disconnect it and put a fused jumper and see if the 4x4 light then comes on,
Customer: replied 6 years ago.
bad switch on the transfer case - :)
Expert:  kevin replied 6 years ago.
thats good to hear, thanks and please hit accept so I can get credit. Thanks and good luck
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