Disconnecting main engine wiring harness

sdw

Registered User
I have been trying to disconnect the main wiring harness from the firewall so I can re and re the dash but cannot get it apart.

Does anyone have any, never fail tricks, to getting this thing apart?

tia

Sean
 
Oh yes, it just won't come apart. I am thinking of a mini pry bar, but am having trouble finding one.

I have pulled dashes before but don't remember having this much difficulty.

sean
 
If the bolt in the center spins but it doesn’t loosen, then the nutsert inside may have come loose. If that happens, it is very difficult to get it apart, and breaking it apart means you will still need to replace the connector end. When it happened to me, the only way I was able to get it apart was by spinning the bolt with an air ratchet while prying it away from the firewall at the same time, it eventually worked its way apart, and then I had to replace the connector end on the dash side, and re-tap the bolt in the engine bay side.
 
This makes sense.

The bolt doesn't really seem like it is loose but I have spent too long turning it for it not to be.

Now to figure out what to do to get it apart. I will try prying it while turning the bolt and see what happens.

Urgh!!


sean
 
Finally apart!

took about an hour 3/8 inch saw at a time.

Can I remove the wires from the inside connector easily-ish?

I would like to use the connector from the 89 dash, when I swap the wiring into it.

Sean



IMG_4541.jpg
 
The dash side connector is held into the firewall with 3 tabs. You have to depress them all at the same time for the harness to disconnect from the firewall.

Usually this is the biggest pain point for the removal...never seen that before with the bolt :eek::eek:.

-Tim
 
Tim:

What I was looking to know is how difficult it is to remove the wires from one connector and put them into another connector.

I have the dash out and am going to swap the wiring from the 91 dash to the 89 dash but don't want to use the old connector due to the spinning nut issue.

regards

Sean




The dash side connector is held into the firewall with 3 tabs. You have to depress them all at the same time for the harness to disconnect from the firewall.

Usually this is the biggest pain point for the removal...never seen that before with the bolt :eek::eek:.

-Tim
 
Can I remove the wires from the inside connector easily-ish?

You'll need to de-pin each wire...there are tools that help w/this, and once you get the hang of it, it's fairly easy.

Good video on the process: https://www.youtube.com/watch?v=PB6KcLSCAGU

Example tools: https://www.ebay.com/itm/Automotive...hash=item213c917530:m:me0hJ2wKFWIBbHH7gfWx_Xw

The pin on the end of each wire usually has an small angled piece that sticks out on the side...when inserted into the connector, that piece bends and then when the end is fully plunged, it snaps outward to lock into a recess in the connector, preventing the end from being forced out when the connector is mated up to the harness. Note that some connectors have an insert on the inside that needs to be removed first, before you can go after the wire end. Some have a soft rubber gasket on the outside of the connector that you'll want to work out before starting to help see what you're doing...don't forget to replace them when re-pinning.

The tool is a properly sized tube, or fork/blade that fits over or next to the end, forcing the bent piece out of place so you can pull the wire and it's end out of the connector. There are different tools for different ends - some are round, some are flat and some are square, and they can come in different sizes. You'd match the tool with the end...push it in far enough to release the clip/retainer, then pull the wire from the connector.

It's a good tool and skill set to have/learn on these older cars as the connectors age and can break their clips/keepers just taking one off the harness....it's a problem waiting to happen when connectors don't have their keepers to insure the wires/ends aren't full plunged. Being able to replace broken connectors (assuming you can find spares) and being able to swap wiring in a harness such as you want to do helps keep them on the road.
 
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Thanks so much for the reply.

I have the wiring out of both the 91 and the 89 dash will put the 91 wires into the 89 dash tomorrow then aquire tool and swap out the connectors, then pop dash back into the car!

Regards

Sean


You'll need to de-pin each wire...there are tools that help w/this, and once you get the hang of it, it's fairly easy.

Example tools: https://www.ebay.com/itm/Automotive...hash=item213c917530:m:me0hJ2wKFWIBbHH7gfWx_Xw

The pin on the end of each wire usually has an small angled piece that sticks out on the side...when inserted into the connector, that piece bends and then when the end is fully plunged, it snaps outward to lock into a recess in the connector, preventing the end from being forced out when the connector is mated up to the harness. Note that some connectors have an insert on the inside that needs to be removed first, before you can go after the wire end. Some have a soft rubber gasket on the outside of the connector that you'll want to work out before starting to help see what you're doing...don't forget to replace them when re-pinning.

The tool is a properly sized tube, or fork/blade that fits over or next to the end, forcing the bent piece out of place so you can pull the wire and it's end out of the connector. There are different tools for different ends - some are round, some are flat and some are square, and they can come in different sizes. You'd match the tool with the end...push it in far enough to release the clip/retainer, then pull the wire from the connector.

It's a good tool and skill set to have/learn on these older cars as the connectors age and can break their clips/keepers just taking one off the harness....it's a problem waiting to happen when connectors don't have their keepers to insure the wires/ends aren't full plunged. Being able to replace broken connectors (assuming you can find spares) and being able to swap wiring in a harness such as you want to do helps keep them on the road.
 
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