Where to add 30 amp accessory

jclars

Registered User
I am adding an air ride system to my F100-SC and need to tap into the electrical somewhere. The compressor requires a 30 amp fused circuit and the solenoids to the air valves will require a separate 15 amp fused circuit.

What is the best way to add these circuits?

I have abandoned several items during my build, including the ride control system, the ABS and the passive restraint. However, I cut those circuits at the front left hand kick panel terminal. Would any of these be ignition activated and not interfere with other stock electrical items?

Thanks,
John L.
 
Add another fuse block direct off the battery and use a relay with a trigger off the ignition.
 
Got the relay in place. Where is the best pick-up point for the keyed ignition circuit?

After my initial posting I removed my LH kick panel and there are two available battery power souces that I had clipped at the square terminal plug. One is a 12 ga yellow wire and the other is 12 ga red w/light blue stripe. These were abandoned when I moved the wiring harness. Any harm in picking these up for the battery source?

Thanks,
John L.
 
I too would go with a completely separate fuse/box. I would suggest either hot in RUN or as I've come to like hot only with engine running.

I re-purposed the OEM oil sender to supply a switched ground to a relay. This way I don't have to worry about excessive load without the system charging.
 
I attached the schematic I am following. Can the switched ground as suggested work with this layout?


What about the two available hot wires from the LH kick panel terminal. Closer than going to the battery.

I will definitely add a separate fuse block as suggested. Still wondering how to accomplish the switched side however.

Thanks for the assist.

John L.
 

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That schematic also has a switched ground, so yes adding another to the supply side would work.

The easiest way to do it would copy thier drawing and 86 go to the OEM oil sender (I used a tee since I also have a autometer gauge), 30 still be HOT either RUN or CONSTANT, 87 continue on to aux fuse box or straight on to their relay/fuse.


So if you want only to be triggerable with engine running need a OEM oil sender, another relay with ground going to sender and power passing through relay to either aux fuse box supply or your compressor relay/fuse supply.

I would use a DPST relay so you can add a bypass if you need to.

The oil sender closes at 7PSI so you could put in on anything that goes of 7PSI. Oil does this immediately but could add to coolant if want to control something based on engine being at operating TEMP.


40A service tells me you need 10AWG minimum, so IF those LH panel wires are that size then ok but I doubt they are. OEMs use the smallest wires they can get away with and not necessarily the proper wire size, obviously not a safety issue but a load/supply concern.
 
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Thanks for the input. I think the 40 amp relay is a one-size-fits-all approach by the compressor people, as they use the same relay for dual compressor applications. My single compressor is rated at 20 amps. The inline 30 amp fuse is also being used.

So I went ahead and tapped into the 12 gauge kick panel wire for power. I found a 16 gauge keyed wire in the same location to activate the relay, and got the compressor running. I am going to add a manual switch to this line to allow remote shut-off.

Next up is wiring the four air valve paddle switches! These are installed in the upper console extension I made to match the Super Coupe interior. I am also installing a 6" screen receiver/DVD in this upper console which pretty much fills it up! I will post pics of it when it is finally trimmed out.

Thanks for the continuing assistance I get from this board!

John L.
 

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So I went ahead and tapped into the 12 gauge kick panel wire for power.

I don't know what a 12 gauge kick panel wire is, is that a wire off the EEC-IV harness? If so, it's not a good idea to be using it for anything but sensors. The EEC-IV has relays with separate power circuits for all accessories. Any switched power coming off of it is used as the signal for for the separate power circuits or for constant power driving sensors.

Accessories should be run directly off the battery on their own fused circuit. Something like a compressor should be treated like a cooling fan with it's own dedicated battery connection IMHO.
 
I will recheck, but the 12 ga wire as well as the 16 ga keyed circuit were/are coming from the LH side of the harness as mentioned above. I mounted everything the same as in the T-bird logistically just for this purpose - tracking things down with folks who are knowledgeable about the SC systems.

When I "pruned" the SC harness, I started in the rear and worked my way forward, leaving behind the the bare necessities like lights and gas pump. And inertia switch. Most of the wires led to the RH kick panel connectors. I believe they may have fed power to the ABS computers and the Amp above the trunk deck. Since these were power circuits, I didn't think they would be coming via the EEC, but there is still a great deal of wrapped wires that are hard to trace without unbundling.

As originally stated, the power wire was red with a light blue stripe. The smaller keyed wire was tan with a red dashed line.

Thanks for the heads up!

John L.
 
Red/Blue I wouldn't only use as a trigger and not a supply (mainly used as power for windows, moonroof, and trunk).

Tan/Red is ABS I believe.


By what I've seen the only wire even close to proper size (that I would feel safe repurposing) is Black/Orange.

You should be fine using those as signal but need a new supply. I've thought of running a 0AWG wire to a distribution block for add-ons.

Not saying won't run but believe voltage drop will be too great.
 
I'm listening. This is the first "modern" car I have torn into, so just learning how to interpret schematics in the EVTM - thanks for helping me understand it.

It appears the block of wires I have been referring to is in the Primary Junction Block. I see on Page 40 where the R/LB wire is identified as a 20A circuit for the windows/moonroof.

I am now looking at the Yellow wire that leaves this block and wondering what the service is on that one? Can't seem to isolate where it heads from the primary junction block. Any thoughts?

Thanks,
John L.
 
By what I'm reading Yellow is: EEC, Seat Belts, Fan, Radio, Headlights, Fuel Pump, Horn/Hazards, Memory(cluster), Defrost, ABS, Ignition Switch, ARC.

Yellow is the main power wire.

Do you think its big enough to run all that?
 
I will have to relook to see if there isn't a stripe on the yellow wire, as it is presently clipped at the junction box. That was confusing to me when I reviewed the EVTM as it showed powering all those items you listed, but it is a clipped wire and yet I am using everything listed except ABS, ARC and defrost. It is the same gauge wire as the R/LB one that was mentioned earlier. However, I think the Yellow wire shows much more amp rating for what it is serving.

Fun, fun.

John L.
 
Yellow/circuit 37 does do a bit of splicing and pass through several fuses so that could be it.
 
Found a wiring diagram. Yellow going to pin 8 on the IRCM and coming from the power distribution box is the EEC 30Amp fused circuit and powers the EEC.

Red with a light green stripe is a 30amp fused circuit going to pin 16 on the IRCM and from the Ignition Coil fuse in the power distribution box. This swtiches the EEC power relay and provides switched power 12v to the DIS and coil.
 
Red/Lt blue that I clipped at the primary junction box would most logically have come from the moonroof, power windows and trunk lock. Possibly the keyless entry system as well. These were all eliminated from my project vehicle.

The yellow wire in question may have fed the passive restraint system or the rear window defrost. Both these were snipped out of the system. Looks like these may be a stouter circuits (40A), but I am going to try and trace it back from the junction box to see exactly where it originates. There are yellow wires at the amplifier that were eliminated as well, but I don't think I actually severed any of the radio wires, knowing I would need that harness later. (The EVTM lists the amplifier circuit as 30A.)

None of these wires appear to originate from the IRCM or ECC. They are in the bundle of wires which originally travelled from the PD penetrated the firewall through a round bolt through connector on the RH side of the engine bay. Of course, they may have travelled through the ECC connector, and then across under the dash, but that doesn't appear to be the case.

John L.
 
Seen this, right?
'Auto Shocks' would be a great donor for air bags :)
-=-

attachment.php
 
Yeah, I saw that, and the label would be perfect, but it may be routed through the EEC, which I am trying to avoid. Although, as I say that, I think I recall removing a ride control box, which may mean it was independent. Thoughts there?

I am focusing on utilizing the available wiring at the junction box, as I have made an effort at zippo wires inside the engine bay. Hot rod obsession, I know. And the junction box is very convenient for wiring access with routing under the dash, through the console and down under the truck where the air ride components are mounted. (My truck had a battery box below the passenger side floorboard which made a perfect "mechanical room", with factory access at the floor panel.

The trouble I am having with the EVTM is understanding all the splice points and what that means for actual service. I have eliminated all splice points from the junction box back for these particular wires. But there may remain some upstream, which I am trying to trace/confirm.

John L.
 
The 'Auto Shock' PCB 30A output from there goes to the relays for the actuators only, I think, so if you abandon the output to the stock harness and tap in DIY, you can go to your compressor w/o fear?

As for the EEC, the EVTM page for the ride control module says the EEC connection (pin 28) isn't used.
 
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