tjones8611

I understand the solenoid causing a vacuum, thus the removal of the vacuum places the truck in 4hi, however, what causes the truck to engage in 4lo?

I cant seem to get the truck in 4lo but 4hi is working fine.

kmc

What year model and is it mechanical or electronic shift? 2004 - 2006 have an electronicmagnnetic clutch and relay. The 4wd indicator switch is located on the transfer case. Could be your not getting the electrical implus on the low side, if your sure it is not just the indicator switch and that your already in 4 low and the light is just not lighting up. I`d check the switch and connections.

tjones8611

Its a 2006, with the 4hi / 4lo switch on the dash.

kmc

Well look at the switch on the dash put a meter on it. I`d remove the switch and make sure I`m getting contact when I switched to 4 lo. Sounds like your not getting a impluse on the lo side if the hi side is working fine.

kmc

If your not sure on how to remove it go to a parts store and look for a repair manual .

Montano

Do you have the truck in neutral with your foot on the brake when you try to put it in 4 LO ?

f150baller

is it bad to just switch into 4hi while your driving?

Beretta84

I think its fine to switch into 4 HI while your driving as long as you're not going any faster than 55 i think. I still wouldn't do it on dry pavement though.