VDO Gauges
Overhauling the VDO gauges that came with my 323i. I'm not really sure where this kit was sourced from. Someone suggested Bav Auto but I also found the 3-gauge housing on a Mazda RX-7 forum (Retro-Spec gauges).
In any event I had to overhaul this kit as I had two troubling issues: the voltmeter was dead (short circuit when I was probing for voltage at the pins) and the oil temp and pressure gauges were showing erroneous values (both were off the charts). As I pulled the gauges from the dash I found a rainbow of colored wires and questionable connectors. I also found disconnected wires and broken/frayed wires. It was good enough for awhile but now needed all new wiring and maybe new parts too.
VDO is well-known so there was no trouble finding gauges. I bought from eBay but I think I received counterfeit parts. The gauges look right but the packaging is very generic. I suspect these are knock-offs. I also failed to realize I had white needles and I ordered gauges with orange. Doh!
I swapped the voltmeter out first and sure enough the new one worked perfectly. I had shorted the old one by accidentaly touching the positive and negative posts together. A new oil pressure gauge did not fix its issue, however. So I must have a problem with the sender located on the engine. That is TBD.
For wiring, I bought 14 gauge spools from Home Depot in red, black, and green colors. Each gauge needs power and ground. Each bulb also needs a power and ground tied into the light switch. The oil temp and pressure gauges each need a data wire from the sender. The voltmeter just reads volts from power and ground. Simple but that's 5 wires per gauge (minus one for the voltmeter) - a lot of wiring in a small space. The VDO instructions online were overly simplistic and not very helpful. For example, power should be sourced from "the positive terminal on the battery (after the ignition switch, and after the fuse box)". Is it at the battery, at the ignition switch, or at the fuse box? Why not just say, "source 12 volt power from a power source activated by the ignition switch". I think this confused the original installer of my gauges because he wired it directly to a fuse terminal (see photo) below) instead of tapping an existing wire on that circuit. Anyway, it worked for awhile... I built new harnesses with correct colors, tight connections, and heat shrink. Everything powered up on the first test but the oil gauges were still having issues that I need to work out.
To be continued...
Read MoreIn any event I had to overhaul this kit as I had two troubling issues: the voltmeter was dead (short circuit when I was probing for voltage at the pins) and the oil temp and pressure gauges were showing erroneous values (both were off the charts). As I pulled the gauges from the dash I found a rainbow of colored wires and questionable connectors. I also found disconnected wires and broken/frayed wires. It was good enough for awhile but now needed all new wiring and maybe new parts too.
VDO is well-known so there was no trouble finding gauges. I bought from eBay but I think I received counterfeit parts. The gauges look right but the packaging is very generic. I suspect these are knock-offs. I also failed to realize I had white needles and I ordered gauges with orange. Doh!
I swapped the voltmeter out first and sure enough the new one worked perfectly. I had shorted the old one by accidentaly touching the positive and negative posts together. A new oil pressure gauge did not fix its issue, however. So I must have a problem with the sender located on the engine. That is TBD.
For wiring, I bought 14 gauge spools from Home Depot in red, black, and green colors. Each gauge needs power and ground. Each bulb also needs a power and ground tied into the light switch. The oil temp and pressure gauges each need a data wire from the sender. The voltmeter just reads volts from power and ground. Simple but that's 5 wires per gauge (minus one for the voltmeter) - a lot of wiring in a small space. The VDO instructions online were overly simplistic and not very helpful. For example, power should be sourced from "the positive terminal on the battery (after the ignition switch, and after the fuse box)". Is it at the battery, at the ignition switch, or at the fuse box? Why not just say, "source 12 volt power from a power source activated by the ignition switch". I think this confused the original installer of my gauges because he wired it directly to a fuse terminal (see photo) below) instead of tapping an existing wire on that circuit. Anyway, it worked for awhile... I built new harnesses with correct colors, tight connections, and heat shrink. Everything powered up on the first test but the oil gauges were still having issues that I need to work out.
To be continued...
