VDO Gauge wiring Guru's, Need Oil Pres / temp help Options

[ahdoman]

I'm in the process of re-wiring my gauge console after a harness rebuild. Anybody know how I can use both the VDO oil pressure gauge and the idiot warning light in the stock gauge? It doesn't seem to work to wire them in series because the idiot light sees voltage and sends that to the gauge making it spike to the far right.

Anoother challenge - Being the perfectionist that I am I would also like to use both the VDO oil temp gauge and the temp gauge in the stock gauge. Why? Because I can't stand to see a gauge not working. If you wire those in series they both read a shared value showing the wrong (lower) temp. Any ideas?

[Aaron Cox]

idiot light - green wire that goes to the oil pressure switch at the oil cooler boss on case.

temp gauge in the combo gauge, as seen in 914/6, and 2L cars sold without center consoles or ordered with that option....

green wire with red stripe IIRC, connects to the motor via a 'taco plate'. taco plate is on the bottom of the motor, off to the side, similar to the sump plate, but is secured with 2 screws. you need the kind with the boss for the temp sender.

[ahdoman]

idiot light - green wire that goes to the oil pressure switch at the oil cooler boss on case.

temp gauge in the combo gauge, as seen in 914/6, and 2L cars sold without center consoles or ordered with that option....

green wire with red stripe IIRC, connects to the motor via a 'taco plate'. taco plate is on the bottom of the motor, off to the side, similar to the sump plate, but is secured with 2 screws. you need the kind with the boss for the temp sender.

Aaron-
I've got all the right wires and switches. I'm just trying to do a non-stock configuration so this is going to require some custom wiring. I was hoping someone else may have already done this and would provide some insight.

[fiid]

Hey,

There is no oil pressure sender on a 914 that is stock, to my knowledge. There is a VDO sender that has both a pressure sender AND an idiot light switch - which is what you want. You'll have to run an extra wire (or use another wire although I doubt you have one spare) for the oil pressure guage.

As for the temp gauge, I think you will only be able to run one, because of the way the wiring works inside the gauge. Basically - the sender acts as a resistor to ground, and the gauge has a resistor in it that connects the sender to 12v and measures the voltage. By having two gauges, you have to resistances between 12v and the sender, which basically means you are reducing that top resistor value. There are new, accurate gauges and senders that fit the 914 well and can be made to fit in the stock center console - If I were you, I'd would consider just doing that.

[John]

I agree with fiid.

There is a dual sender (gauge + light) that will do what you want. It can mount in the same location as the original oil pressure light switch. You will need to add a wire (or use another) for the gauge.

Two temp gauges from the same sending unit: Someone once posted in a thread that it could be done with some use of diodes. I have never tried that. When I had 2 gauges connected to the same sender, both gauges gave 1/2 readings.

Good luck to you.

[jasons]

You will need the VDO dual sender with a new wire as state previously. But, you will probably need to extend it out of the tin, because it doesn't fit through the hole. Some people have used a brake line to do it, some people have used hardware from Home D. to do it. If you use the brake line, you have to ground the sender somehow. I used a steel braided brake line. It provides its own path to ground.

[ahdoman]

Does the dual sender have 2 poles on it? If so, what are they marked? Which pole goes to the gauge and which to the idiot light?

[jasons]

Does the dual sender have 2 poles on it? If so, what are they marked? Which pole goes to the gauge and which to the idiot light?

Yes, marked G and WK

G goes to gauge
WK goes to light. I think it means warnen klampe or something like that. Basically, warning lamp. A German speaker can correct me.

See the VDO Dual senders HERE. There are 2 depending on the gauge you use.