After swapping out the transmission truck will not start

Tiny
15DOMINICP
  • MEMBER
  • 1990 GMC SIERRA
  • 200,000 MILES
Okay so my truck is the short bed step side single cab. Currently has a 350 in it and had a five speed manual. Swapped it to a th400 transmission and everything went together and plugged in smoothly. Got a 1994 steering automatic steering column and put it in and plugged everything in. Everything works on the truck powers everything but will not start. I hooked up a starter switch and started it off that and it started right up. So I tried jumping the clutch pedal switch and it still will not start I have tested everything and done research and cannot figure it out or how to by pass the metrical safety switch for it to work.
Saturday, March 11th, 2017 AT 8:56 PM

6 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Putting the later model steering column in may be the problem. They are both obd 1 but the wiring for certain things may have changed. Especially in ignition. Check wiring on ignition lead from old column to new one. I cannot tell you how to jump safety switches.
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Sunday, March 12th, 2017 AT 8:54 AM
Tiny
15DOMINICP
  • MEMBER
  • 4 POSTS
I mean it is a 1990, but alright thank you.
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Sunday, March 12th, 2017 AT 9:00 AM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
That is what I said in first reply check wiring from column that was removed to wiring in new colum to where they hook up. Purple to purple on other.
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Sunday, March 12th, 2017 AT 9:44 AM
Tiny
15DOMINICP
  • MEMBER
  • 4 POSTS
I did that. And everything has matched up everything is doing what it should, except for sending power to starter.
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Sunday, March 12th, 2017 AT 10:19 AM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
It is the purple wire that goes to start on start cycle. If you have hooked up wiring to transmission then it lies in that area or the column. That is why I said check wiring there due to using a new column.
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Sunday, March 12th, 2017 AT 10:43 AM
Tiny
15DOMINICP
  • MEMBER
  • 4 POSTS
Got it. One of the pins for the ignition plug in the column was bent and was not getting connection. Everything else plugs in correctly from a 1990 truck to a 1994 steering column thanks for the help.
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Sunday, March 12th, 2017 AT 4:04 PM

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