Looking for additional unfused ignition locations

[imholte]

I have a 72 k10 and just put in a new aluminum radiator and am working on the dual spal fan install.

The install instructions have a connection to the keyed ignition power. No problem I will just run it to the fusebox and put it to one of the unfused igniton tabs (with a inline fuse). When I get there I see that I used both of the unfused ignition tabs for the HEI and the Echoke on the weber carb (I think, its been 10 years since i put that in).

So the big question is can I just tie in to one of the wires leaving the box for the HEI or carb choke or is there a better way to do it.

The new radiator and fan look great but then when compared to everything else it looks pretty bad.

[Andy4639]

Depending on how you want the fans to work? There are several opitions for fans.
Do you have them hooked up to a temp probe? Are they going to run seperate one for the normal cooling and one for when AC is on will need to know all this for a good answer.

[Husker]

Run a wire from your ignition to a Bosch type relay so that it only runs when truck is running. Run a a wire from your battery the other side of the relay for power for the fan. Mount the relay close to your fan. The power to energize the relay is minimal. If you want to only run fan when it needs to cool install a temperature switch in the block somewhere and run the ignition jumper through it, when it reaches the temperature of the switch relay will turn on.
Relay come in different amperage ratings.
Ron
https://www.ebay.com/itm/GM-Relay-Ha...sAAOSwQeha6hW4

[70STOVEBOLT]

Find the spot in the bulkhead connector on your firewall (engine side) wherecthe original ignition power wire is/was. Remove the connector and plug your HEI power wire into that spot. You will need to get a male Packard 56 connector for 12/10 gauge wire.

[davepl]

I'd run a separate wire and I'd make sure it's fused. You don't want a problem with a fan shutting down your ignition circuit. Plus, according to my fusebox, it's labelled IGN UNFUSED and you don't really want a bunch of unfused stuff anyway!

I assume you have a relay for each fan and we're talking about the trigger wire? Normally, you'd power the fans right off the battery to the relays and the only power from the harness is to trigger them ON, not to power them.

[imholte]

The fans came from Old Air products, https://www.oldairproducts.com/produ...-72-50-7230s-7
and they come with a complete wiring harness with relays, all you have to do is connect one to the fans, the battery, the temp switch, and the ign on (trigger) switch.

I just wanted to know the best option for connecting the ign wire since the two locations in the fusebox are taken up. Since the power to run the fans is coming from the battery would it be okay to just add this wire to the others on the fusebox (ign unfused tabs) or would that draw too much off of them and cause problems.

[imholte]

Originally Posted by 70STOVEBOLT

Find the spot in the bulkhead connector on your firewall (engine side) wherecthe original ignition power wire is/was. Remove the connector and plug your HEI power wire into that spot. You will need to get a male Packard 56 connector for 12/10 gauge wire.

I will see if I can find this and try hooking up the HEI to this, that would free up one of the unfused ignition tabs in the fusebox.

[imholte]

Originally Posted by davepl

I'd run a separate wire and I'd make sure it's fused. You don't want a problem with a fan shutting down your ignition circuit. Plus, according to my fusebox, it's labelled IGN UNFUSED and you don't really want a bunch of unfused stuff anyway!

I assume you have a relay for each fan and we're talking about the trigger wire? Normally, you'd power the fans right off the battery to the relays and the only power from the harness is to trigger them ON, not to power them.

Correct, they came with all the fuses and wiring, I am just trying to find the best place to connect the trigger wire, I thought it was best to use the IGN UNFUSED tab in the fusebox (and put an inline fuse in) but both of mine are in use. Just need to know if I connect another wire to one of the ones coming off of the wires connected to the IGN UNFUSED that it wont draw too much off and cause problems.

Thanks for your help.

[Andy4639]

I ordered a 10 fuse holder then hooked it up to the unfused circuit. I then ran all my accessories off of it and everything was fused.

Mine doesn't have the LED lights though.

[imholte]

Originally Posted by Andy4639

I ordered a 10 fuse holder then hooked it up to the unfused circuit. I then ran all my accessories off of it and everything was fused.

Mine doesn't have the LED lights though.

Thank you, good idea

[davepl]

Originally Posted by imholte

Correct, they came with all the fuses and wiring, I am just trying to find the best place to connect the trigger wire, I thought it was best to use the IGN UNFUSED tab in the fusebox (and put an inline fuse in) but both of mine are in use. Just need to know if I connect another wire to one of the ones coming off of the wires connected to the IGN UNFUSED that it wont draw too much off and cause problems.

Thanks for your help.

If, as I said, you're just talking about triggering the relays from the IGN terminal and the actual fan power will come from the battery or junction block, then you're in terms of current.

The amount of current it takes to turn on a relay coil is maybe 150mA as a guess.