Strange connection adapters on "rear AC" fuse. Your best guess welcome.

377 Views 19 Replies 10 Participants Last post by ehbrown1, 6 d ago

augidog

Discussion Starter · 8 d ago (Edited)

1994 LT AWD.

receipts show new AC within the last year.

clutch not engaging.

when driving this home after buying it, we experienced a parasitic draw that killed the (already weak) battery during a long lunch. i was desperate for a solution. I found this weird connection adapter on the "rear AC" fuse, two small tabs pushed onto the fuse blades. the wires are the ones on the floor. Both this one and "AC" fuses are good.

I can't imagine why this fuse would be chosen for an accessory tap , especially off both sides of the fuse. there is paperwork indicating an aftermarket alarm system, no longer working. i found no other add-on connections, and this is why I disconnected those wires. i hesitate to re-connect them because i wasn't paying attention to polarity when i took them off.

Does anyone have a best guess? could this be some sort of quick-fix that affects the compressor clutch?

thank you for playing.

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MechBob

· #2 · 8 d ago

Cannot imagine it has anything to do with the A/C clutch.
As far as your A/C, key on, engine off, a/c on, see if there is power to one of the 2 wires on the low pressure switch. If so, jumper them and see if clutch engages.

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sixsix

· #3 · 8 d ago

Augi, not really sure what we are looking at. The 2 wires w/ conns... the orange wire/tape beehive... the fuse upside down...?

AstroOafAdventurer

· #4 · 8 d ago

What are those red & orange wires with non-OE looking spade receptacles?
Looks like they're in reach and may have been connected.
Why one would tap into that fuse I have no idea...

Big_kid

· #5 · 8 d ago

Only way to know for sure is to follow the wires- they definitely don't look factory. Upfitters, maybe. The ONLY reason I could think of tapping both sides of a fuse like that would be to go to a circuit breaker in case the fuse blew. Makes absolutely NO sense to do that though. Maybe they're both power feeds to something else, one fused and one (hopefully) has a fuse of it's own being that it's on the hot side of the fuse it's tapping.

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bryancraftyhands

· #6 · 8 d ago

Could take a jumper pack to the wires in question, and connect them to test for polarity, and see if they turn anything on, draw current, etc.

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augidog

Discussion Starter · #7 · 8 d ago (Edited)

sixsix said:
Augi, not really sure what we are looking at. The 2 wires w/ conns... the orange wire/tape beehive... the fuse upside down...?

hard to see with the bad pic, maybe after description...there are two strips of copper, definitely manufactured (but by who?) to slip over the fuse blades. when you reinsert the fuse, you have two male spade terminals. the two wires laying on the floor were connected to the "adapters" which are on the "rear AC" fuse. i said a prayer the two "accessory" wires may be identifiable by color. if anyone had ever seen this before they'd recognize it and may know what it's about.

if you (like me) had never seen it before, you might think (like me) that it was an accessory tap for the aftermarket alarm, but in a horrible location (why would anyone choose to tap power off that particular circuit with other easier options?)

thanks to all for the technical guesses. i think the same as you....unrelated to the AC issue. my initial instinct was to disconnect them as possibly the parasite drain, i just felt the need for validation.

Rod's Trucks

· #8 · 8 d ago

augidog said:
hard to see with the bad pic, maybe after description...there are two strips of copper, definitely manufactured (but by who?) to slip over the fuse blades. when you reinsert the fuse, you have two male spade terminals. the two wires laying on the floor were connected to the "adapters" which are on the "rear AC" fuse. i said a prayer the two "accessory" wires may be identifiable by color. if anyone had ever seen this before they'd recognize it and may know what it's about.

if you (like me) had never seen it before, you might think (like me) that it was an accessory tap for the aftermarket alarm, but in a horrible location (why would anyone choose to tap power off that particular circuit with other easier options?)

thanks to all for the technical guesses. i think the same as you....unrelated to the AC issue. my initial instinct was to disconnect them as possibly the parasite drain, i just felt the need for validation.

Without any other ideas, or suggestions, I would disconnect one, and see if you can determine ANYTHING that might stop working. Then I would try the other wire, looking for the same result.
IMHO, 'Something' should stop working, or they went to something that has been removed or disconnected.

Rod J
Issaquah, WA

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sixsix

· #9 · 7 d ago

Just went back and looked at the pic again - I did not see the (2) brass spades sticking out from the conn. for the RR Heat. I read it - and as is the case now & again - missed your stating it. doh.
Maybe whoever at least stuck with "GM style" wire colors - as was mentioned.
Just wondering - is this on your Van or the one you were helping with recently. Not that it changes anything, but tracing back the wires seems your only recourse. Oh wait - '94... so you said that too. double doh...

I'll be over there with my string and piece of cardboard...

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sixsix

· #10 · 7 d ago

?

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augidog

Discussion Starter · #11 · 7 d ago

i haven't traced any wires yet, but i have a thought. being red and orange, is it possible the rear blower circuit melted and this is a "do-over?"

someone who has rear heat/AC may have a clue.

sixsix said:
?

triple-d'oh!

right now it's in the shop for a full once-over...delete oil cooler lines, possible cracked radiator, cruise-control stem/turn-signal switch, exhaust...

AstroWill

· #12 · 7 d ago

augidog said:
found this weird connection adapter on the "rear AC" fuse, two small tabs pushed onto the fuse blades. the wires are the ones on the floor. Both this one and "AC" fuses are good.

Pretty standard aftermarket kit back in the day. https://amzn.to/43BloQz

augidog said:
i hesitate to re-connect them because i wasn't paying attention to polarity when i took them off.

No polarity worries, both of those tabs would be positive.

augidog said:
could this be some sort of quick-fix that affects the compressor clutch?

Not likely.

Big_kid said:
Maybe they're both power feeds to something else, one fused and one (hopefully) has a fuse of it's own being that it's on the hot side of the fuse it's tapping.

This would be my guess, only one side would be protected by the fuse, the other side should be immediately removed and never connected to that space again as it would only really be protected by a fusible link behind the battery that is way to large to protect that wire. That wire that is probably craptastically run under the carpet without the electrical or physical protection that it should have.

augidog said:
i haven't traced any wires yet, but i have a thought. being red and orange, is it possible the rear blower circuit melted and this is a "do-over?"

It's just as likely that it could be for the schmuegen board, or the disco lights.
It's 100% aftermarket, could have been from the conversion company(kinda doubt it), or it was from a PO that didn't know what they were doing and half arsed it.

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realityguy

· #13 · 7 d ago (Edited)

What about this..maybe why it is in the AC spot..
Looking at a wiring diagram for the rear AC(95 and later) shows a Pink/orange combination going through an AC enable relay(pink in)into an under the hood fuse/relay center to orange.. back to the enable relay and continuing on with dark green to the AC diode and A/C Compressor clutch...
Perhaps a bypass for a bad relay(under the hood) for the hot all the time or hot/in run or start relay? Perhaps a road mechanic with a quick fix..?
Make sense why your clutch wouldn't work now?
Shows under the hood a IGN minifuse H7 and A/C Comp K11 both 10 amp..

I'm no electrical genius..call it a hunch why it is put there?

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augidog

Discussion Starter · #14 · 6 d ago (Edited)

AstroWill said:
Pretty standard aftermarket kit back in the day.

it's clearly a manufactured item, and we have paperwork for an old (non-functioning) "Viper" alarm. still, you cannot technically tap accessory power that way, unless as mentioned both are separate hot wires with one being fuse-protected. also, there's much easier ways to tap into an old-school fuse-block.

realityguy said:
Perhaps a road mechanic with a quick fix..?

i think this may be close to explaining the situation. what we're looking at could make technical sense if there is no power to or from the fuse (perhaps the original wiring is toast? are rear blower circuits also prone to overheating?) and the red wire is the new source with the orange wire being the new feed to the circuit. it's in the shop now for the important fixes, so this "AC" mystery is on hold. the wires will stay disconnected until i can get at it with my meter and do some backtracking.

btw, those slip-on terminals caused the sockets to permanently spread...without them the fuse won't stay. so no matter what we wind up doing, they have to remain.

AstroWill

· #15 · 6 d ago

AstroWill said:
Pretty standard aftermarket kit back in the day. https://amzn.to/43BloQz

augidog said:
it's clearly a manufactured item, and we have paperwork for an old (non-functioning) "Viper" alarm. still, you cannot technically tap accessory power that way, unless as mentioned both are separate hot wires with one being fuse-protected. also, there's much easier ways to tap into an old-school fuse-block.

Yes, I provided the link to the exact product from Dorman. Viper alarms are good stuff, made by DEI. I would not imagine that a professional installer would use those on an alarm system, and esp to tap the wrong side of the circuit. I agree, it should have been tapped into the system properly, not hard to do. I can definitely see someone putting an extra power outlet, powering their trailer hitch connector, disco light or whatever that way.
Either way, the non-fused side should never be used even if you have to keep the tabs in there so the fuse is tight. Do it correctly or have someone else do it correctly, definitely worth sleeping better at night.

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augidog

Discussion Starter · #16 · 6 d ago (Edited)

AstroWill said:
I can definitely see someone putting an extra power outlet, powering their trailer hitch connector, disco light or whatever that way.

the factory wiring is in the rear storage along with the factory jack and accessories, all pristine, so i suspect this wasn't a tap for towing. the only two conversion add-ons i see are a manual sunroof and running boards, no mood-lighting or disco balls.

my first quick inspections didn't tun up any other taps or splices at the block or nearby. i have found a mess of small wires with an inline fuse and a couple switches that looks to be what's left of the alarm, under the dash. i pulled that fuse but haven't traced anything yet. i'll hope everything tracks back to those two wires, meaning i've eliminated the defunct alarm setup.

i'm still open to the possibility that the two wires are a "fix" to a rear AC or heater issue, so i'm still curious if the rear circuitry is subject to high-speed burn-out like the front fan circuitry. i have zero experience with the rear heater and AC, so please pardon the possibly stupid question.

staying true to the subject title, this is all still guesswork. i have not been given enough time and access to fully investigate the situation.

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realityguy

· #17 · 6 d ago

This is what I was looking at when I posted above about maybe a " fix".. Maybe a problem with the under the hood relay? while someone was on the road done by a small city repair shop( and maybe mentioned to the driver about what was done "temporarily" until he could get it repaired properly.."we don't have that relay...")..so they bypassed it to get the AC working again but put it in that location for a service person with the proper parts could find it/fix it easier.

I think I'd check the under the hood relay box or ahead of the AC enable relay.Wouldn't that bypass make it work again? Anyway it was just a hunch of why it might have been put THERE.. I'm talking bypass at the pink/orange wire point in the diagram.. Did you possibly find another unknown short wire to fit between the two ends with a 10amp fuse wired in..,,or the 10amp fuse was jammed in also in the fuse box? maybe those two wires going under the hood might have been cut and spliced with a fuse..?I don't know..but I'd check that...especially if the AC clutch doesn't work now. I would think you'd have power on one wire... the other side continues on the dark green to the diode and AC/Compressor clutch that now isn't working...
My logic may not match others..!

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Rod's Trucks

· #18 · 6 d ago

I have used similar 'fuse tap' devices in several vehicles, with excellent results, and easily reversible (no mod or damage to original setup) when desired. If very much power is needed, just use the taped source to control a relay.

www.amazon.com

Amazon.com: 5 Pack 12V Car Add-a-Circuit Fuse TAP Adapter Mini ATM APM Blade Fuse Holder : Automotive

Buy 5 Pack 12V Car Add-a-Circuit Fuse TAP Adapter Mini ATM APM Blade Fuse Holder: Fuse Holders - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

Rod J
Issaquah WA

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ehbrown1

· #19 · 6 d ago

Have seen people do all kinds of bizarre things to fuses and wiring.

ehbrown1

· #20 · 6 d ago

It's doubtful that was a circuit tap as it was connected to both sides of the fuse, but anything is possible today.
Have seen people do that and parallel a circuit breaker over the fuse for a troublesome circuit that keeps burning out fuses.

You do that when you're too lazy to figure out why that fuse keeps blowing.

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