full time light blinking

I have 1991 xj when i put it in full time four wheel the light will flash on and off after a few minutes when i let of the gas it will stay on for a few minutes and then it will act up again I am new to this your help would be appriciated

Mine does the same thing with both FULL TIME and PART TIME lights. The 4WD system itself works flawlessly, but the lights flicker sometimes.

I'm pretty sure it's just a short or loose wire behind the dash somewhere, I've more or less decided to just live with it.