Instrument voltage regulator question

Does this look wired correctly? It seems like an extra wire tti the oil gauge. One wire from the regulator and obe from the harness. 67 series 1. Oil pressure doesnt worvk.


Something sure seems funny. Temp and fuel are regulated to 10v. OP should get 12v.

Typically the 12V ignition source comes into the IVR input. The output goes to the fuel and temp gauges. The OP gauge gets 12V ignition, but it is picked up at the input to the IVR. There is only one input connection and one output connection to the IVR. But both connectors have two redundant male spades. The input gets 12V, and also serves as a junction to feed the 12V to the OP gauge. The output splits to the two gauges that are voltage regulated. One side of yours has two wires inserted into one female spade, so that the second male spade isn’t used. I don’t know whether it is input or output.

Ah after a second look I think all is good! It comes out of the harness and goes to IVR in. OP is on that same lug. IVR out uses only one lug but it looks like both the wire for the temp and the wire for the fuel are duplexed on the same lug and share an insulator. I couldn’t see the one going to the fuel as it dips under the fuse diagram.

Thank you, i ordered a new regulator from Cool Kat and ordered a new OP sender. I dont know what else could be the problem.

Good. But as Erica says, the IVR isn’t in the OP circuit at all.

Yup, I’d cancel that regulator order assuming fuel and temp are working fine…although the digital regulator works a charm and is even adjustable. The sender however is a likely culprit.

I figure ill keep it to make sure fuel and temp gauges are accurate

What does the adjustment do?

The analog VRs are temperamental, and don’t always deliver a precise 10v, so those two gauges can read a bit off. The adjustment pot on the digital one allows you to trim it to exactly 10v using a meter.

An extremely nerdy point, but I can’t help making it because you rarely get a setup like this:

The old OEM IVR is a switching regulator. It’s digital–binary 0 or 1, It uses pulse width modulation to produce an average 10V. Quite modern principle (and widely used) except the Jag version is implemented with mechanical, not transistor, logic (bimetallic heater; contact strips).

The electronic versions (at least in the recent past) use integrated circuit series regulators that provide a continuous output voltage, fixed at 10V or adjustable. That design is analog but has no moving parts, making it more reliable.


Kinda pointless, however, given how imprecise the gauges and senders are…

Ray L.


Stop parading in my rain :stuck_out_tongue:

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