95 K3500 4X4 engagement ?

[gsl56]

I had a problem with the engagement of my 4X4. I replaced the actuator which helped. The light never comes on to indicate engagement but it is in 4 wheel. I have checked the bulb. I must stop and put into park to either engage or disengage. If I don't stop it will not engage or disengage. Is this normal? What acuates the indicator lamp?
TIA for your help.

[craigix]

I've never used my 4x4, but tonight i shifted it into 4x4 and nothing seemed to happen, should i feel anything? Curious about it now.

[amac209]

there is a switch on top of the diff that should turn the light on. on trucks with 5 wires at the actuator the switch is part of the actuator. try unpluging the switch and jumping the 2 terminals with a paperclip if the light works the switch is bad, if no light you have a open wire somewhere.