1994 Jetta Check Engine Light!

I have a 94 Jetta GLS 2.0L that will not start unless the check engine light is on.. To get it to turn on I have to smack yes hit punch kick the dash area under the steering column .. This was no big deal until the other day when the check engine light started to go off while driving. Let me tell you kicking the dash while driving is annoying any ideas on what is wrong??