Temperature guage

M37UK · Post by **M37UK** » Thu Jan 15, 2009 10:00 am

Something not right with my replacement temp guage and sender. I have wired it up as per manual but after a little while the actual guage gets really warm!

Any ideas what I could have done wrong?

I have live wire to one terminal of guage then wire from the other terminal to the sender.

Stuart

m-37Bruce · Post by **m-37Bruce** » Fri Jan 16, 2009 1:52 pm

I think one wire should go to ground? (inside the dash?)

M37UK · Post by **M37UK** » Fri Jan 16, 2009 3:04 pm

Thanks Bruce

I'll give that a try tomorrow.

MSeriesRebuild · Post by **MSeriesRebuild** » Fri Jan 16, 2009 3:16 pm

M37UK wrote:Something not right with my replacement temp guage and sender. I have wired it up as per manual but after a little while the actual guage gets really warm!

Any ideas what I could have done wrong?

I have live wire to one terminal of guage then wire from the other terminal to the sender.

Stuart

You have it wired correctly, there is no ground wire, the sender is grounded via the engine block, the gauge is grounded through the case to the panel. You may want to check for a proper ground, however there is no dedicated ground wire.

M37UK · Post by **M37UK** » Sat Jan 17, 2009 1:56 am

Charles, does it matter which terminal connects to the sender and which terminal connects to live?

Carter · Post by **Carter** » Sat Jan 17, 2009 4:38 am

Gauge testing info:

http://www.cj3a.info/sibling/milgauge/milgage.htm

MSeriesRebuild · Post by **MSeriesRebuild** » Sat Jan 17, 2009 8:42 am

M37UK wrote:Charles, does it matter which terminal connects to the sender and which terminal connects to live?

Yes you must have the correct leads to the correct terminals or you can have a major melt down. Carter has posted some very good easy to understand descriptions & diagrams that you can follow according to which guage you need to troubleshoot. Check that out & let us know if you need further assistance.

M37UK · Post by **M37UK** » Thu Jan 22, 2009 1:14 pm

Had a look at the guide but it doesnt actually state which gage terminal is for which connection.

I presume it doesnt matter which one you use.

Stuart

N1VSM · Post by **N1VSM** » Thu Jan 22, 2009 3:18 pm

M37UK wrote:Had a look at the guide but it doesnt actually state which gage terminal is for which connection.

I presume it doesnt matter which one you use.

Stuart

Yes, it does. One is for 24V in, the other comes from the sender. Plug it in backwards and you will release the mystic smoke that makes all electronics work (and perhaps start a small fire, too). If you have the metal connectors (Douglas), there is no way to mess this up. With the rubber (Packard), it should also be rather clear: one connector is male, the other female. I'll try to remember

to take a look & see which is which.

I got so frustrated finding a gauge/sensor combination that worked, that I'm switching over to a mechanical gauge. Wish I'd seen the gauge testing stuff earlier - I've already made the investment in the mechanical one.

M37UK · Post by **M37UK** » Fri Jan 23, 2009 7:08 am

what happens when the packard connectors look like this? No obvious male and female terminals?

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M37UK · Post by **M37UK** » Fri Jan 23, 2009 7:11 am

N1VSM, what type of mechanical guage did you go for?

Stuart

N1VSM · Post by **N1VSM** » Fri Jan 23, 2009 9:30 am

I have a Stuart Warner 701-2185 gauge. It looks original, but is expensive. This one has a 48" tube on it - they also come 72" (701-2184) an 144" (701-2182).

I see your problem on the inputs for the gauge. Looking at the gauge from the back with the gauge upright, my (dead) electric gauge has the female socket on the left and the male socket on the right. One of these gets a constant 24V from the spider harness. Unfortunately I've forgotten which one.

I'll try to remember to check after I go skiing. In the mean time, maybe there's someone else who knows??

DaveO · Post by **DaveO** » Fri Jan 23, 2009 12:43 pm

Stuart,

Looking at your photo, notice the rubber recepticle on the left has raised lines running on the length of the outside. On my M38A1 OP gauge, this is the side that the sender plugs in. The rest of my gauges are Douglas, so no help there.

I remember trying to figure these plugs out before, and thinking it odd that the hot wire (from the spider harness) didn't go to the recepticle with the ridges. My mind wanted to put hot to the "marked" terminal.

HTH

Dave

achiem37 · Post by **achiem37** » Sat Jan 24, 2009 9:31 am

the gauges are made to hook up correctly into the wiring harness. wire # 33 should go to the sender at the back of the engines head. the other wire is # 27 and comes from the dash spider assembly. the connectors are male/ female with the wire # 33 being a male side connector. the douglas connectors should allow these wires to be hooked up only in the right direction. here is a schematic that might be helpful ( hope it works)
http://m37.crwdesigns.com/m37wiring.pdf

M37UK · Post by **M37UK** » Sat Jan 24, 2009 1:31 pm

Are the gauges in that schematic shown as viewed from the front or back?

Stuart

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