E12 Auxiliary Gauge Cluster FAQ

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Courtesy of Adam Wilson


This FAQ is intended to give some guidance on building your own set of auxiliary gauges in the E12 5 series. This particular gauge cluster was built using VDO gauges and senders. I purchased mine from BMP Design. These gauges were installed in my former E12 528i, now owned by Tulsa Dave. I had a huge help from my friend Jeff Herrmann a BMW CCA member who knows all about custom installs from his car stereo days. He did all the wiring and provided the guidance for me to build this gauge setup.

VDO Gauge example

The material needed to construct your gauge cluser is fairly thin particle board available at any Home Depot. Making a template out of the area below the radio in the E12 center console is the first step. Cut the wood to the appropriate size and then make your gauge cluster in the form of an enclosure with the aim of having your gauges sit inside this enclosure. The pictures will give a better indication of what I am talking about. We used wood glue for building the enclosure first and then after the glue set, we used bondo (body repair gunk available at any Pep Boys or auto parts store) to shape the three pods for the enclosure.

Area under radio in center console, formerly occupied by the ashtray on a US spec E12 5 series
Initial, glued together assembly for gauge enclosure
Rear of initial gauge enclosure
Initial gauge enclosure, note pencil outlines of gauge holes
Slop the bondo on there, it'll all get sanded later after it dries

After using the bondo to make a rough outline of the pod enclosure, the next task is to sand, sand, and then sand some more. ANY imperfections will be evident through the vinyl once applied. With my enclosure, the goal was to have three distinct pods that had visible contours. However, we didn't build up the surface quite enough to make the three pods, so once the vinyl was applied, there weren't any contours really visible. The sky is the limit for how much effort you want to put in this. If you just want three holes, then there is nothing wrong with that. But building up the pods will create more of a polished, professional install appearance. Once the sanding was finished, we used hole drill bits to make the pod holes for the gauges in the enclosure. We tried to ensure a very snug fit for the gauges in their holes so that we didn't have to use any glue on them to get them to stay in there. Remember, you can always take away material but you can't put back. The holes we cut with the hole bit were too small but we sanded until we could just barely fit the gauges in the holes.

Gauge enclosure after sanding dried bondo to a smooth finish
Holes cut in enclosure for our three gauges

Once the holes are cut and the gauges fit, we used 3M spray adhesive in a can on the entire enclosure to attach the vinyl. We went to a fabric store and found some decent, black/charcoal colored vinyl that we used to trim the gauge enclosure. Cutting it to fit was a bit of a pain, especially with the contours for the pods. The spray adhesive works extremely well (sticky!!) so positioning the vinyl once you put it on, will be quite difficult. For this reason, try to ensure that you are going to be able to take care of any wrinkles in the vinyl before you apply the spray adhesive.

Test fit the enclosure in the space below the radio!
Finished product with wiring, vinyl attached

I do not have any pictures of the installation of the senders, but I felt they were self explanatory. The oil temp gauge is a drain plug which replaces the stock drain plug in the oil pan. We soldered a wire to this which was routed through the firewall to the oil temp gauge. A word of advice for oil changes. Some kind of connector by the drain plug will help with unscrewing the drain plug. The sender for the oil pressure replaces the stock sender. It has two terminals, one for the stock "idiot" light, and one for the new oil pressure gauge. You will need to hook up power to the gauges, and ensure than the connection for the gauge back lighting is hooked up to the circuit that will allow the dash lights to fade in and out when you turn the headlight switch.

Gauges installed in E12.
Crude night photo of gauges lit up after install in the car

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