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1G Battery relocation cable through firewall.

El Cuervo

Proven Member
551
16
Nov 7, 2004
Omaha, Nebraska
Hi guys. I have a question. I'm relocating my battery to the trunk on my 1g. My question is:
For those that have 1g DSMs. Where or how did you route your cables through the firewall?
I read that some have route the battery cable through the hole that's close to the clutch and brake pedal on obviously the driver side firewall. Well, I have my boost gauge wire, my LC1 wideband wires and my fuel pump rewire though that hole with a grommet. It's a very tight fit already. Though, I'll be removing that 10gauge wire from the hole since the battery will be in the trunk, it's still way too small for the battery cable to to through it, with all the other cables from the boost gauge and the wideband.
So how did you guys do it? Did you end up drilling a hole through the firewall? If so, where at? Or is there another location?

Thanks in advance guys.
Cheers.
 

El Cuervo

Proven Member
551
16
Nov 7, 2004
Omaha, Nebraska
You have to push it through with a good bit of effort but it can be done. I used the same gauge of wire. Having another person could make it easier but I did it by myself. I'd suggest putting the wire in through the engine bay side first so you have a lot more room.
Oh. Ok. Would you happen to have a picture on how it looks? Like a picture of the wire harness with the cable going through it from the engine bay.
That would be great!
 

91tsiawdtalon4g63

Proven Member
170
23
Dec 24, 2013
Brownsville, Pennsylvania
This is probably the best pic I have. I have all the wires going to a distribution block (thing holding the wires on firewall). But I have the battery wire through the engine harness hole feeding into the block.

Screenshot_20210407-154439_Gallery.jpg
 

91tsiawdtalon4g63

Proven Member
170
23
Dec 24, 2013
Brownsville, Pennsylvania
Using this photo from google of dave's old car, you'll just put the power wire through that hole. Real easy.

Otherwise could probably just drill a hole in the firewall a little bigger size than the wire and run it through there. Previous owner of my other current car did so and has it running underneath where all the blower motor and hvac equipment is placed under the dash (all of that stuff is removed currently).

Screenshot_20210407-155529_Chrome.jpg
 

El Cuervo

Proven Member
551
16
Nov 7, 2004
Omaha, Nebraska
Awesome! So you just made a hole on the wire harness rubber grommet boot thing and routed the cable through there?
 

jakelandry

Proven Member
936
126
Oct 13, 2009
Minden, Louisiana
There are quick disconnect bulkheads for this. I would advise against running it through the firewall near the engine harness. Although unlikely, depending on the quality of your grounds and whatnot, you could introduce electrical noise into your sensor wiring.
 

El Cuervo

Proven Member
551
16
Nov 7, 2004
Omaha, Nebraska
There are quick disconnect bulkheads for this. I would advise against running it through the firewall near the engine harness. Although unlikely, depending on the quality of your grounds and whatnot, you could introduce electrical noise into your sensor wiring.
Interesting. So what do you suggest?
 

jakelandry

Proven Member
936
126
Oct 13, 2009
Minden, Louisiana
Interesting. So what do you suggest?


You could also use a -12 an fuel bulkhead or wire pass through. I’ve just never been a fan of anything loose or just “stabbed through a boot” in my car.
 

El Cuervo

Proven Member
551
16
Nov 7, 2004
Omaha, Nebraska


You could also use a -12 an fuel bulkhead or wire pass through. I’ve just never been a fan of anything loose or just “stabbed through a boot” in my car.
Makes sense. I'll look into it. My thing is that I'm trying to avoid drilling a hole on the firewall. But this is definitely an option.
Thank you very much for the idea.
 

spyderdrifter

Supporting Member
5,104
615
Jul 11, 2009
Some where, Colorado
Not a 1G, but still an idea for you. I've routed the cables to the trunk for mine too. I'm doing a wire tuck and moving things around and no longer need the oem harness hole in the firewall for the harness. I have now routed my cables through it and will be searching for a apiece of rubber for a grommet.
 

El Cuervo

Proven Member
551
16
Nov 7, 2004
Omaha, Nebraska
Not a 1G, but still an idea for you. I've routed the cables to the trunk for mine too. I'm doing a wire tuck and moving things around and no longer need the oem harness hole in the firewall for the harness. I have now routed my cables through it and will be searching for a apiece of rubber for a grommet.
So, how are you routing your harness wires from the ECU, to the enigne Bay? So you are using the stock wire harness hole for the battery cable (s).
And the wiring from the ECU to the engine bay, such as sensors and all that? How will you route these?

Thanks man!
 

spyderdrifter

Supporting Member
5,104
615
Jul 11, 2009
Some where, Colorado
So, how are you routing your harness wires from the ECU, to the enigne Bay? So you are using the stock wire harness hole for the battery cable (s).
And the wiring from the ECU to the engine bay, such as sensors and all that? How will you route these?

Thanks man!
Since I'm redoing the harness, there will be a cannon plug bolted to the fire wall for quick disconnect. The oem harness hole will no longer be used for the harness. I will probably get a sheet of steel to cover the oem hole as well, so that the opening is smaller, and drill holes in that for the battery cables, and whatever else I send through it.
 

El Cuervo

Proven Member
551
16
Nov 7, 2004
Omaha, Nebraska
Since I'm redoing the harness, there will be a cannon plug bolted to the fire wall for quick disconnect. The oem harness hole will no longer be used for the harness. I will probably get a sheet of steel to cover the oem hole as well, so that the opening is smaller, and drill holes in that for the battery cables, and whatever else I send through it.
That's very nice.
You'll have lots of room for other things such as gauges, wideband and other cables that need to go though the firewall.
 
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