Power (Switched & Floating) : Wiring Advice

[TimeMachinE30]

I've read Luke's posts, didn't see what I think I am looking for.

Will be putting in three VDO gauges, cubby mounted.

Some say not to tap into stereo power, may cause sound quality issues. Where shall I get my power, floating/dimming and switched? Is it best in this case to run a piggy back fuse box? I do have this piece but it is fed constant (from old alarm system). If I go off the cig lighter, will the gauges add too much draw?

I have a bundle of OEM wire pulled from an E46. Trying to make everything kosher, seeking out most "way the factory would have done it".

Thanks.

[Jb325is]

I took mine from un-used pins on the large square connector under the dash on the drivers side. I can't find a picture of it, but it's a huge white connector that accepts multiple smaller connectors on the front side.

[TimeMachinE30]

I took mine from un-used pins on the large square connector under the dash on the drivers side. I can't find a picture of it, but it's a huge white connector that accepts multiple smaller connectors on the front side.

Awesome, I'll look around.


It would be cool to build a connector, too. The gauges have 5 connections each (light power, ground & sender & gauge power, ground).

PS: Everytime I see you post, I think back to a buddy from college who lived in Marietta. Stayed at his place once or twice...

[TimeMachinE30]

https://www.rbracing-rsr.com/wiring_ecu.html

Oh Lord, been doing everything all wrong.

[Jb325is]

Yeah, don't worry about all that stuff. The motorsports stuff is stupid money and ridiculously over-complicated. The cars I work on all have $10k+ harnesses with DTM and autsport connectors throughout, while the connectors are very nice and easy to assemble/dis-assemble, you run into a lot of issues with serviceability with the harness in general. Troubleshooting and repairing damaged parts when everything is potted/glued all to hell is a real pain in the ass when the harness starts getting a little older.

If you do want to build connectors, get some good crimpers and Deutsch connector tools, it's a little expensive at first but the connectors are well worth it.

Marietta is a pretty cool place, I live pretty far outside of town but come here for work and bars/restaurants. Can't complain.

[StereoInstaller1]

Does your car not have the auxiliary fuse block?

[TimeMachinE30]

The piggyback on the fuse box ynder the hood?

[StereoInstaller1]

Yes, one is constant, the other ignition

[george graves]

Some say not to tap into stereo power, may cause sound quality issues.

Scratching my head why that would happen...Ok I can think of maybe one or two instances where that could happen....one is if the gauge is using a DC-to-DC buck/boost converter. But knowing VDO, they aren't going to do that. Just to keep cost down, and to avoid just that issue.

I'd run it from the ACC of the radio harness. I'd hate to see someone run an extra wire through the firewall if it's not needed. Runnign through the firewall means you need to sheath it, and make it look pretty. And then give yourself a disconnect as well.

[TimeMachinE30]

Yes, one is constant, the other ignition

Only piggyback I have there is the constant. Too bad, I would really like to make everything seem stock. Then again, hiding the wiring.. out of sight out of mind and seamless?

Scratching my head why that would happen...Ok I can think of maybe one or two instances where that could happen....one is if the gauge is using a DC-to-DC buck/boost converter. But knowing VDO, they aren't going to do that. Just to keep cost down, and to avoid just that issue.

I'd run it from the ACC of the radio harness. I'd hate to see someone run an extra wire through the firewall if it's not needed. Runnign through the firewall means you need to sheath it, and make it look pretty. And then give yourself a disconnect as well.

I appreciate you two for chiming in on this. I will Do ACC off the radio. Dimming? Ground I will run to the glove box. Is there ever an issue of a ground being overused?

T-taps seem bleh. Soldering best method to tap into these existing lines? I don't mind the extra work. This is all a therapeutic thing for me.


All the gauges and senders are in hand.

I did order a pack of 6 pin Deutsche connectors in an attempt to clean up install, make insertion/removal easier and general tinkering.

[george graves]

I appreciate you two for chiming in on this. I will Do ACC off the radio. Dimming? Ground I will run to the glove box. Is there ever an issue of a ground being overused?

Soldering best method to tap into these existing lines? I don't mind the extra work. This is all a therapeutic thing for me.


All the gauges and senders are in hand.

I did order a pack of 6 pin Deutsche connectors in an attempt to clean up install, make insertion/removal easier and general tinkering.

There is both constant power, ACC, ground, and dimming(pretty sure that is standard on all e30s with a radio - if not, the ash tray will have a dimming wire) on the radio harness. Your VOD gauge(s) will sip power(ok 100mA each if they aren't LED based, much less if they are the new design), so I wouldn't worry about connecting everything there - you'll be fine. BTW, that connector, it's not like is some magical, isolated separate circuit. It comes from the fuse box like everything else.

I'm not going to get into connection types, as Luke will have another aneurysm about how his butt-slices are the only way to go on everything. And if you disagree with him you'll forever be on his shit list. Choose the right connection/method for the job. Each type has it's place. *cough*solder*cough*

As far as grounds, sure you can overload a ground wire. When you might want to run a separate ground is when the thing you're hooking up also needs a lot of power. Like a seat heater, an amp, or such.

[TimeMachinE30]

Thanks GG.

I recall the connection issue. Milspec, avionics, marine, automotive, radio, hobby, audio... they all have their own do it this way or that. I am going to crimp some (new hydraulic crimping tool too!), solder some.

The Deutsche connectors arrived. Pretty stoked to try them out. I will have time to tinker again..... say in January. :sad:

The T Tap or vampire connectors seem hated across the board. I will do the solder approach there: peel back the insulation, feed slave wire through the feed wire, etc. (didn't see a routine name for the method).