Replaced Dash Harness and now no start

[HeloCrewChief]

I decided to replace my under dash harness since the fuse block was so corroded none of the fuses were even fully held in. I purchased an M&H unit and the install was pretty straight forward. Even with the corroded fuse block I was stilla ble to start the truck every time and the headlights, dome light, horn, and taillights worked. No dash lights worked.

After replacement, the truck does not start. Almost like a dead battery or bad starter. The only light I get anywhere is the brake light in the instrument cluster which did not previously work. Being optimistic about it at least something now works

Anyway, I've tried jiggling the ignition harness around and that did nothing. The truck is a manual transmission so, I do not think neutral safety switch is an issue. I'm thinking about pulling the fuse block back off and trying to reconnect it with the engine harness again to see if that helps.

[davepl]

Power comes in via the big red in the bottom right corner of the harness (facing the firewall from outside). Check that first - it's connected to the junction block, alternator, all of that.

Then check the opposite side of it (don't know the color offhand, but it should be obvious) and make sure it's coming through on that wire.

[demian5]

No magic pill here, you are gonna have to diagnose and recheck everything.

Anything anyone says would be a shot in the dark.

Good luck.

[badd71]

I put the inside fuse block in upside down once.

[cleszkie]

Does the new wiring harness come with provisions for a neutral safety switch for an automatic transmission? If so, then you will need to jump the wires to fool it into thinking the neutral safety switch is closed. Otherwise, you will not be able to start the truck.

[HeloCrewChief]

Originally Posted by cleszkie

Does the new wiring harness come with provisions for a neutral safety switch for an automatic transmission? If so, then you will need to jump the wires to fool it into thinking the neutral safety switch is closed. Otherwise, you will not be able to start the truck.

There is an extra plug that was not on my old harness in the steering column vicinity. You may be on to something there. I will try jumping that plug and see what happens.

[Toms67]

You probably already checked this. Make sure all your ground wires are hooked up. And you have a good ground contact to the block and the frame. Hope this helps.

[MySons68C20]

[MARKDTN]

Originally Posted by cleszkie

does the new wiring harness come with provisions for a neutral safety switch for an automatic transmission? If so, then you will need to jump the wires to fool it into thinking the neutral safety switch is closed. Otherwise, you will not be able to start the truck.

x2.