C5 cooling fan power wiring schematic
Thread Starter
Le Mans Master
Joined: Apr 2001
Posts: 5,000
Likes: 1
From: Minneapolis, Mn USA
C5 cooling fan power wiring schematic
I'm looking to see if anyone would have scanned or have an electronic copy of the V+ side power routing for the radiator cooling fans.
Im looking to see specifically where the power connection is physically made, and what fusible links or fuses are in the pathway.
I did a MARK VIII electric fan conversion on my C3 last year and used the heavy starter lug as the fan circuit power source. This is a direct battery connection and no fusible links with the very heavy gauge wire. However there is a fusible link from the alternator BAT+ to the starter lug BATTERY + terminal. Not sure if this fusible link is at risk with this set-up.
So the circuit is like this:
FROM BATTERY VIEW:
(BAT+ on Heavy starter lug)-->(New fanwiring with 65A circuit breaker)-->(75A relay)-->(Fan)
FROM ALTERNATOR VIEW:
(ALT BAT+)-->(Fusible link)-->(BAT+ on heavy starter lug)-->(New fanwiring with 65A circuit breaker)-->(75A relay)-->(Fan)
I'm looking to see how GM did it in great detail, whether it was a direct alternator connection and fused from there, or a direct battery V+ connection and be fused from there.
Im looking to see specifically where the power connection is physically made, and what fusible links or fuses are in the pathway.
I did a MARK VIII electric fan conversion on my C3 last year and used the heavy starter lug as the fan circuit power source. This is a direct battery connection and no fusible links with the very heavy gauge wire. However there is a fusible link from the alternator BAT+ to the starter lug BATTERY + terminal. Not sure if this fusible link is at risk with this set-up.
So the circuit is like this:
FROM BATTERY VIEW:
(BAT+ on Heavy starter lug)-->(New fanwiring with 65A circuit breaker)-->(75A relay)-->(Fan)
FROM ALTERNATOR VIEW:
(ALT BAT+)-->(Fusible link)-->(BAT+ on heavy starter lug)-->(New fanwiring with 65A circuit breaker)-->(75A relay)-->(Fan)
I'm looking to see how GM did it in great detail, whether it was a direct alternator connection and fused from there, or a direct battery V+ connection and be fused from there.
Thread Starter
Le Mans Master
Joined: Apr 2001
Posts: 5,000
Likes: 1
From: Minneapolis, Mn USA
Thread Starter
Le Mans Master
Joined: Apr 2001
Posts: 5,000
Likes: 1
From: Minneapolis, Mn USA
Im trying to determine where GM pulls its power from for the electric fan circuits.
1) Battery side of fusing
2) Alternator side of fusing
The big difference is the location of the main fuses, which are not included in the diagram attached above.
In the C3, there is a large fusible link between the Alternator BAT+ terminal and the starter heavy lug, which is a direct Battery connection with a heavy gauge wire.
I installed a fan which has a large additional draw and made my connection from the starter lug. Just tryin to see if I should be upgrading my Alternators charge wire from Alt to starter lug or pulling my dedicated fan circuit directly from the Alt connection.
There is logic to both set-ups and Im trying to see which way GM went.
1) Battery side of fusing
2) Alternator side of fusing
The big difference is the location of the main fuses, which are not included in the diagram attached above.
In the C3, there is a large fusible link between the Alternator BAT+ terminal and the starter heavy lug, which is a direct Battery connection with a heavy gauge wire.
I installed a fan which has a large additional draw and made my connection from the starter lug. Just tryin to see if I should be upgrading my Alternators charge wire from Alt to starter lug or pulling my dedicated fan circuit directly from the Alt connection.
There is logic to both set-ups and Im trying to see which way GM went.
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Thread Starter
Le Mans Master
Joined: Apr 2001
Posts: 5,000
Likes: 1
From: Minneapolis, Mn USA
Bill
YES!!!! This is exactly what I needed. A HUGE Thank you for this.
BTW, My next Vette will most likely be a late model 03 or 04 Z06 with the steel shift forks in the tranny. Hope the comeradery on the C5 side is as good as it is on the C3 side.
Thanks again!
Best Regards, Brent.
YES!!!! This is exactly what I needed. A HUGE Thank you for this.
BTW, My next Vette will most likely be a late model 03 or 04 Z06 with the steel shift forks in the tranny. Hope the comeradery on the C5 side is as good as it is on the C3 side.
Thanks again!
Best Regards, Brent.
3rd Gear
Joined: Aug 2018
Posts: 3
Likes: 0
Hi-speed fans aren't coming on
Thanks. Let me be more specific in what I'm trying to do.
My fans actually work in hi speed straight wired to a battery, but is not coming on as should (at any temperature) wired to OEM specs. I think I may have a broken connection between my fans and the fuse/relay box. My question is where's that wire or how do i find it if i need to maybe rewire?
My fans actually work in hi speed straight wired to a battery, but is not coming on as should (at any temperature) wired to OEM specs. I think I may have a broken connection between my fans and the fuse/relay box. My question is where's that wire or how do i find it if i need to maybe rewire?
3rd Gear
Joined: Aug 2018
Posts: 3
Likes: 0
It's been tuned on the dyno and has done great for a couple of years
Fuses and relays are all in the same fuse box (under hood) so those wires are internal to the fuse box. The wires from the fuse box to the fans are shown, including wire colors, in the diagrams I posted.
The control of turning the fans on at specific temps is in the PCM and it uses the engine temp sensor to know when to change the fans from off to low speed and/or to high speed. The temps for low speed and high speed are programmable in the PCM and they may not be coming on because the high temp setting has not been reached. From the factory that temp is 235* F.
The control of turning the fans on at specific temps is in the PCM and it uses the engine temp sensor to know when to change the fans from off to low speed and/or to high speed. The temps for low speed and high speed are programmable in the PCM and they may not be coming on because the high temp setting has not been reached. From the factory that temp is 235* F.
