Electrical Installation
Been working slowly on the wiring of my unfinished CMC speedster. I have no idea what the seller sold me on the wiring harness he sent with the collection of parts. Like so many of the advertised parts, they are questionable or wrong. The front harness and rear sections look correct, but the middle section, which goes under the dash looks more like something one would see in a Cobra kit car, which has more gauges. The number of wires make no sense to me and also, none of the colors match with my CMC/Fiberfab wiring diagrams or follow their color coding.
I have used the front and rear wiring harness sections as they were easy to figure out, even with incorrect colored coded wires. I am not happy with the way the wiring harness was put together as I know VW used separate fuses to each headlight, one for low and one fuse for high beam, on each headlight. This wiring harness only has one wire, which feeds both headlights and no fuse set up for doing the low and high beam on separate fuses. Also, the wiring gage seems small, compared to what VW used originally. But, I am going to bless it and pray it works. I put one 15amp fuse from the fuse box to the light switch. Does anyone besides me note there is no adjustment on the replica light switch to dim the instrument lights ?
Perhaps, some speedster owners use the original VW light switch and that does contain the rheostat to dim the dash lights. Not a big deal as I prefer the full bight lights on the instruments.
Okay, I said I found the main wiring harness wrong or just a big mess to work with. I found two old 1970's Beetles, pulled off the main wiring harness and using two of the front fuse box ( on the VW Bug) to the engine compartment, as the length of the wires were not long enough from the stock Beetles. But, I have color coded wires, which follow the Bentley wiring diagram and makes troubleshooting in the future easier. The original VW Bug wiring harness worked really good and has large gage wires. Only missing was the few wires needed to connect the three 914 gauges I have on my speedster. Those are simple to wire up, so no big deal . On the need for wires for the tachometer, oil temperature gauge and any other sensor I put on the engine, I am making up a four wire cable, running it from the dash//fuse box area to the rear of the speedster. That should complete all the needed wires to have all things working.
Since I used a steering column from a 1971 Bug, connecting the ignition switch to the fuse box and to the wires going to the rear of the car was easy. And, using the turn signal switch from the 1971, in the steering column, also made the wiring easy. The arrangement or design of the fuse box, which came with the kit seems to be wrong. VW used at least 12 fuses in their 1972 Beetles. Few of those are joined together, as the replica fuse box has two banks of joined together fuses. It makes poor sense to not have the fuse arrangement the same as found on the Beetles, as the speedster has the same light set up, uses the VW switches, etc. I would rather see a separate fuse for each side of the car on the park or tail lights. The same way VW did it on their Beetles. Not, one fuse for the entire light circuit.
The joined bank of fuses, on the passenger side of the fuse box, the four fuses, those are okay, as they are on, all the time, so can be joined in that ON section, and do provide separate fuses for each circuit or device, like the horn, wipers, etc.
There is a lot of room for improvement on this speedster wiring. Using the bullet proof original VW wiring harness, from the dash fuse area to the rear, provides me with some degree of hope that all will last a long time. I could never figure out the "mid" section of the wiring harness assembly, sent to me with the collection of speedster parts and tossed it completely in the trash can.
Wrong color coding ? How do you figure out which wires goes where ? I used my VOM on continuity setting to test each and every wire on all the wiring harness, before installing it. Picked out wire colors which made some sense to me and tagged them with labeled masking tape. Once installed, I removed the tape. Both ends were labeled to speed up the installation of the wiring. Also, having worked and repaired wiring problems for 40 years on Beetles, really helped me. I have all the VW Beetle color codes in my brain, so that really helped speed up the wiring.
Two days , once I had the wiring harness assembled, as I liked it was the time frame needed to wire the entire speedster. I have pictured a nice grounding strip I bought from O'Reilly Auto Parts. As one needs on a fiberglass body, a place to attach up to 10 ground wires, this is a quality product and easy to install. I used two number 10 sheet metal screws to hold it to the fiberglass under the dash, close to the normal fuse box location. I ran one 10 gage wire from the ground strip to the front metal frame to connect the strip to the car's grounded frame.
So, my suggestions if you are putting together your own complete speedster replica is to use the simple and VW factory colored coded wiring, from some old 1970's Beetle, you find in the savage yard. Or, buy the complete wiring harness for a Beetle and you only need to add four wires, for the added items found on the speedster, so often used on the engine. For me, the "speedster" wiring harness seems fragile and weak, by design. Original wires, from the VW factory last 40 plus years with no TLC. I inspected and tested the VW factory harness, cleaned off the housing and it's good to use.
If any fuses blow, I am replacing the front and rear "speedster" wiring harness, which came with my replica kit with original VW gage wires, with more fuses.
---George K. ----