What wire to tap for a ACC connection?

[whatwrenchwhere]

Hi,

Installing a GPS tracker and it wants a ACC wire that signals the ignition is on. I have an auxiliary power wire to power the unit. I have a 1985 1.9L with the early style of fuses.

Got the dash down, and looking at Bentley and Ignition Wires, and not sure which if any of these is best to tap. Or some other place maybe.

(Also to note, when I put the key in, there is a buzzer, when I turn to first notch dashboard lights light up, and when start engine, all lights/buzzer go off. )

Any advice?

Included some pictures of under dash wiring and Bentley ignition switch wiring diagram.

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[MarkWard]

There is no ACC power, but in your picture the black wire off the ignition with the blue scotch lock connector is key on/ run power.

Those connectors are poor for wire splices. You could also find a spare key on power spade connector on the back of the fuse box or use a piggy back connector. VW used the number 15 for key on power circuits.

[whatwrenchwhere]

@MarkWard

What do you mean 'VW used 15 for key on power circuits'? I looked around but did not see any 15 numbers on fuse box.

Also, I looked at back of fuse panel, and there are 3 free spade piggy back connectors for fuses 7,8, and 9. From looking at the picture below and Bentley, these appear to be used for:
- 7. Radiator Fan
- 8. Interior Lights, Cigarette Lighter, Stoplights
- 9. Emergency Flasher, Radio

So would using fuse 8, and piggyback on that connector give the key on signal?

Thanks - M

[MarkWard]

Look at the wiring diagram you posted. You can see the 15 on the switch. 30 is constant power. 31 is ground, 50 is power during cranking. X has power in the run position but cuts off during cranking. I’d be hesitant to tell you where to grab power at the fuse box on a 40 year old vehicle.

[jlrftype7]

Regarding the Key buzzer, sounds like yours is working. It's a reminder that the Key has been left in the Ignition, trying opening your Drivers Door to get the buzzer system to signal this reminder as a test with your key in the ignition.
Ours will not turn on the buzzer in the Off position unless the Drivers Door is opened.  Once you start the vehicle, you normally get the warning light 'pod' for the Seatbelt to light up briefly, in conjunction with the Buzzer, then it should go off.
Our '84 operates like your '85.

Picking an Ignition Wire Source, don't tap into the Brake Light Circuit- avoid it- this way if your device ever manages to pop a fuse, you're not risking losing the Brake Lights even if you have a separate fuse downstream of the fusebox for your wired device.
_________________
'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto

[ZsZ]

grey/black is key in.
You can modify the wiring to use as accessory
_________________
Zoltan
1.9 MTdi 2wd Multivan (ex Caravelle)
Van since 2006, engine since 2008

[hardway]

Within the DIN system (Deutsches Institut fur Normung), electrical terminal designations are standardized. Kl 15 is ignition on. On our T3s there is no accessory power terminal.

Many newer devices need this switched accessory power as an input. You could use terminal #15 for this purpose. But you run the risk of back-feeding power into 15. You could isolate the circuit with diodes or use a relay with diodes.

Many people use the key in terminal, terminal S st at the ignition switch to provide this input. Then there is no chance for back-feeding power into Kl 15. If you need multiple Accessory power inputs you could use terminal S to switch a relay.

Some ignition switches available today lack terminal S. I have had to install other switches that have S on some T3s. All of the original ignition switches had terminal S. I remove the key buzzer relay on my old T3s and tap into the circuit with a male spade into the relay block.

[hardway]

If anyone wants to understand DIN terminal designations more I would recommend getting a copy of the Automotive Handbook by Bosch. It is a standard reference book for advanced mechanics and engineers.

https://www.googleadservices.com/pagead/aclk?sa=L&...amp;adurl=

https://www.google.com/url?sa=t&source=web&...37Eymn8sql

This book is a very comprehensive reference manual on all aspects of vehicle technology.

[whatwrenchwhere]

Anyone see any issue with this solution?

I had fuse #11 open on a stock piggyback connector that in Bentley looks like 'Turn Signals' and is a 15 on the diagram (key on). I connected the ACC wire to that directly. I connected the GPS Tracker red power to the auxiliary battery and black ground to a bolt under the dash.

When I turn the key, I can see the tracker is online. When I turn the key off, I can see the tracker offline. Auxiliary power works too.

I tested and all seems to work fine. Thanks for all your help.