My 1979 has the blue light under the center of the dash that lights up and says lock. I had one in a 1978 F250 4x4 supercab. The problem is the light does not light up when I am in four wheel drive. I have traced the wire and it is plugged into a yellow three way plug under the dash around the wiper delay box. It goes through the fire wall down the drivers side of the frame and end around the transfer case and is not connected to anything. My manual say is connects to the transfer case and when in four wheel drive the wire is grounded causing a complete circuit. When I touch this white wire with a red strip on to the transfer case it lights up and says lock. It should only come on when I am in four wheel drive were does it connect on the transfer case, I can not locate any terminal area. I have a NP 205 part time transfer case. The parts shop said only they Np203 full time had the light,if so why does my Np205 have the set up but is not connected, were on the NP205 can I connect this wire make the system work ? Need Help.

 

for real, if this is possible for a 205 that would be bitchin i would love the heck out of a lock or a 4x4 light

 

This light was used with 203 t-cases, and it was an indication that the "LOC" function had been selected. There was no 4wd light on the full time 4wd since the case was always in 4wd.
This lead could easily be installed on a 205, or any t-case by simply installing a micro switch to the shift selector, or the sift rail at the transfer case. (this is provided that a twin stick modification had not been performed)
Simply mount this micro switch in a manner that closes when the shifter engages 4wd, and wire one wire to the switch, and that red stip you mentioned to the other side of the switch. Then whenever 4wd is selected, the switch will close, and your light will illuminate.
This actually seems like a real easy modification to perform.

 

if ANY one has a schematic or has done this on a 205 plz post a parts list and a how to and id gladly appreciate you forever and video record every step of they way for all to enjoy and complete

 

My 77 highboy with full time transfercase has it too.

 

Full time 4wd's only recieved the lock light from the factory. The OP's truck probably had a T/C swap at some time in it's life hence the reason for the disconnected wire.

I have never seen or had a part time 4WD 205 case with a lock light.

 

Ed, I was thinking it might be a little more complicated. 4 low is all the way one way, 4 high is all the way the other. Wouldn't it have to be wired more like the interior lights cause it would have to have 2 switches ?

 

Yes it would Mark.

 

I'm pulling my 203 out and putting a 205 in this winter. I was hoping there was some way I could hook this little light back up.

 

it may be possible here is a diagram of the 205 NP205 New Process Transfer Case Diagrams and Information number 32 is 4x4 indicator switch, and heres another linky to pics

 

i thought the 203 was full time? my truck is the one that you have to get out and turn the hubs to engag 4x4. It has the light and it works, so do i have a different case thann i thought? and if i am right and 203 is full time why would it have display? you know that its always in 4x4... i am confused by this mainly because i thought i had a 205 t case.

 

The 203 can have a part-time kit put into it. My current truck has the 203 with a part time kit in it and works great.

 

After reading the articles about having a 203 and 205 twin stick I wish it was in the budget to turn it into a twin sticker, but then again living in Iowa, not many rocks around here to crawl over.

 

Very interesting. I have never seen that switch on a 205.



The 203 is full time, the 205 is part time. There is a tag on the side of the T-case that you can use to identify what case you have. What it sounds like you have is a 203 case. If you have hubs on the front axle then someone put a set of lock outs on it at one time. The reason for the lock light is for when it actually fully engaged in 4wd the light would light up to let the driver know.

AFAIK Ford only used a lock light on the full time 4wd only. I have never seen the light on a factory equipped part time truck.



The T-case on an NP 203 (full time case) will have a shift pattern like this.

4 Lo lock
Lo
N
Hi
4 Hi lock

The NP 205 (part time case) will have this shift pattern

4 low
N
2 high
4 high

 

very interesting, i always whished i had a 4x4 light, and it might be possible?