how to bypass 4hi/4lo switch as a test?

[rastoma]

I recently purchased a 93 S10 Blazer 4x4 with a W engine (4.3 Vortec).

It has 91k miles. This was literally a little old ladies truck. She changed the oil and that's it. It had original everything, fuel filter, wires, cap, rotor..... She don't know anything about 4wd.

Neither light comes on the 4hi/4lo switch when you turn the key on or try to start it. Nothing happens when I press 4hi or 4lo. I am getting power TO the switch and power to the TCCM fuse and to the TCCM itself.

There are 5 connectors on the plug that goes to the rocker switch:

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The middle connector/wire has 12v, the other are dead.

Is this how it should be?

To make sure whether it's a rocker switch problem or not, how would I jump those connectors to see if it goes into 4wd?

[MT-2500]

Originally Posted by rastoma

I recently purchased a 93 S10 Blazer 4x4 with a W engine (4.3 Vortec).

It has 91k miles. This was literally a little old ladies truck. She changed the oil and that's it. It had original everything, fuel filter, wires, cap, rotor..... She don't know anything about 4wd.

Neither light comes on the 4hi/4lo switch when you turn the key on or try to start it. Nothing happens when I press 4hi or 4lo. I am getting power TO the switch and power to the TCCM fuse and to the TCCM itself.

There are 5 connectors on the plug that goes to the rocker switch:

| |

|

| |

The middle connector/wire has 12v, the other are dead.

Is this how it should be?

To make sure whether it's a rocker switch problem or not, how would I jump those connectors to see if it goes into 4wd?

What transfer case?
Ia this a rocker swith or push button switch?

What color are wires.

See if any wires have 12 volts when you press low or high button.

[rastoma]

I don't know what model the transfer case is. Where do I find that info?

The 4x4 switch is a rocker switch on the left of the dash and it does 4HI and 4LO and that's it.

No lights on the switch. I do get 12v on one of the wires GOING to the switch but pressing the switch does not do anything. I did a continuity test using a multi tester and it appears the switch does make contact when going to 4hi and 4lo.

I do not remember the color of the wires but will check tomorrow and post back.

The main thing is no lights are on the switch even though 12v is going to the switch. I get 12v to a couple of different wires on the TCCM as well.

[MT-2500]

Originally Posted by rastoma

I don't know what model the transfer case is. Where do I find that info?

The 4x4 switch is a rocker switch on the left of the dash and it does 4HI and 4LO and that's it.

No lights on the switch. I do get 12v on one of the wires GOING to the switch but pressing the switch does not do anything. I did a continuity test using a multi tester and it appears the switch does make contact when going to 4hi and 4lo.

I do not remember the color of the wires but will check tomorrow and post back.

The main thing is no lights are on the switch even though 12v is going to the switch. I get 12v to a couple of different wires on the TCCM as well.

For a switch test make sure you have 12 volts on brown/white wire to switch key on.
Pressing 4W high should put 12 volts to gray/black wire to TCCM module.
Pressing 4W low should put 12 volts on green/white wire to TCCM

For a switch bulb test ground gray/black wire for 4W high light.
For a bulb test on 4W low light ground purple/white wire.

I only show a rocker switch on a 94 modle
Is this a late 93 or a 94 modle.
What is 10 diget in vin no?
Transfer case has a ID tag on back of it.

4W light should come on key on bulb test.
And if it flashes you have a code stored.

[MT-2500]

Shifting is best done in neutral position.
Neutral saftey switch can block out shifting in park or drive.
Shift to neutral and try it.
And sometomes press the switch hard and two times.
Can you ever hear transfer case shift or go into 4W?