New Wiring Harness-No shift - The 1947 - Present Chevrolet & GMC Truck Message Board Network

coacharmstrong1990 · 09-03-2019, 09:55 AM

I just installed a new BP-Automotive Wiring Harness and the quality and ease of installation is great. My engine was running like crap with the homemade harness but is running great with he new harness. However my transmission has stopped shifting. With my janky homemade harness it would shift but now it will not. could this be TCC lock up issue? maybe i have the pole switched in the brake switch? IIRC the purple wire is going to the 3rd post from the top and the 12v constant to the bottom post?

maybe a fluid level issue?

thoughts, ideas?

87chevy.com · 09-03-2019, 11:32 AM

Tcc would not cause that. Checkyour basics first. Fluid and fuse.
Top post and bottom post? No idea what your talking about. When talking about wires and connector. e specific what connector and what pin number

BigBird05 · 09-03-2019, 12:25 PM

You didn't give any details about what type of truck you are working on. You need to tell us everything about the truck if you what us to try and help.

coacharmstrong1990 · 09-04-2019, 10:57 AM

1968 C10- Gen III 5.3 cammed and 4L80e

got it fixed the main plug was plugged in upside down

*YoungPup1977* · 09-04-2019, 10:21 PM

Quote:

Originally Posted by coacharmstrong1990

1968 C10- Gen III 5.3 cammed and 4L80e

got it fixed the main plug was plugged in upside down

Can you explain what the main plug is, just wanting to know if I ever have this issue I will know what to do. Can you take a pic of this as well. Thanks

ls1nova71 · 09-04-2019, 10:29 PM

Quote:

Originally Posted by YoungPup1977

Can you explain what the main plug is, just wanting to know if I ever have this issue I will know what to do. Can you take a pic of this as well. Thanks

Most likely he's talking about the big round plug that plugs into the transmission itself. It has small detents to keep it from being plugged in backwards, but they are small enough that you can do it. Seen it done a couple of times.

Wildkarde · 09-04-2019, 08:34 PM

i didnt think that was possible, at least you got it fixed.

*YoungPup1977* · 09-04-2019, 10:55 PM

What year of 4L80E is it ? early years ?

Hey LS1 can you answer this too ?

09-03-2019, 09:55 AM	#1
coacharmstrong1990 Registered User Join Date: Aug 2018 Location: Ashland Kentucky Posts: 27	New Wiring Harness-No shift I just installed a new BP-Automotive Wiring Harness and the quality and ease of installation is great. My engine was running like crap with the homemade harness but is running great with he new harness. However my transmission has stopped shifting. With my janky homemade harness it would shift but now it will not. could this be TCC lock up issue? maybe i have the pole switched in the brake switch? IIRC the purple wire is going to the 3rd post from the top and the 12v constant to the bottom post? maybe a fluid level issue? thoughts, ideas?

09-03-2019, 11:32 AM	#2
87chevy.com BMW & ASE Master Certified Join Date: Feb 2004 Location: Houston, Texas Posts: 1,266	Re: New Wiring Harness-No shift Tcc would not cause that. Checkyour basics first. Fluid and fuse. Top post and bottom post? No idea what your talking about. When talking about wires and connector. e specific what connector and what pin number __________________ 1987 Silverado - L83 5.3 w/ 6L80e ,A/C,P/W,P/L,TILT, HID projectors, Wilwood C-10 Pro Spindles w/ 2018 silverado front brakes & C-5 Corvette Rear Disc Brakes 1999 BMW 528i - 5.7 LS1 w/ 4l60e, Ford 8.8 IRS w31 spline posi & FX-r projector retrofit New project: 2006 BMW x5 6cyl AWD to L83 6l80e 4wd to 2WD / RWD A poor man buy's it twice finally got my domain name back, 87chevy.com.... site rework in progress

09-03-2019, 12:25 PM	#3
BigBird05 Registered User Join Date: Aug 2019 Location: Cheraw Posts: 1,300	Re: New Wiring Harness-No shift You didn't give any details about what type of truck you are working on. You need to tell us everything about the truck if you what us to try and help.

09-04-2019, 10:57 AM	#4
coacharmstrong1990 Registered User Join Date: Aug 2018 Location: Ashland Kentucky Posts: 27	Re: New Wiring Harness-No shift 1968 C10- Gen III 5.3 cammed and 4L80e got it fixed the main plug was plugged in upside down

09-04-2019, 08:34 PM	#7
Wildkarde Registered User Join Date: Mar 2018 Location: Ardmore Posts: 100	Re: New Wiring Harness-No shift i didnt think that was possible, at least you got it fixed.

09-04-2019, 10:55 PM	#8
YoungPup1977 Account Suspended Join Date: Jun 2015 Location: No longer here Posts: 1,000	Re: New Wiring Harness-No shift What year of 4L80E is it ? early years ? Hey LS1 can you answer this too ? Attached Images Last edited by YoungPup1977; 09-06-2019 at 01:25 PM.



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