The Mutts kicking my butt

[Sundawg3]

Guys,

Water / coolant temp gauge didn't work, tried two used gauges with no success. Ordered new (in the package from 1986) transmitter still no worky. Today the new gauge came in so I wired directly to the transmitter and ground, no Bueno. Before all this I rang the harness from the transmitter to the gauge and it was fine. Wired from the transmitter to left post looking at the gauge from the front or right looking from the back. I'm assuming the other post is the light? Even tried both posts and nothing.

Could I have received a bad transmitter or am I missing something? The wiring diagrams I see online are grainy and hard to read.

Thanks

Brad

[Hambone]

Check out this topic, maybe it will help.
https://forums.g503.com/viewtopic.php?t=226409

[Sundawg3]

Thanks Hambone!!!

Tried grounding the wire to the sender with no success, yet it rings to the gauge??? The new gauge needle will move with a quick tap of 24 volts but doesn't work in the panel. Found a print I can somewhat read, looks like wire 27 to the right side is power, and it does have power. Left wire rings to sender. Checked ground in a few places still no luck. The Mutt is being difficult.

[rickf]

You should have a hot wire going to the positive terminal on the gauge, then you have the wire to the sender that goes on the negative terminal of the gauge. There is not light in the gauge, the dash lights on the panel are the lights for the gauges. It sounds to me like you are not hooking up the power wire. The gauge IS the transmitter and the sending unit is the ground, The sending unit is a resister and changes value as the temperature changes and hence the resistance changes and the reading on the gauge changes. You should be able to put a meter on the wire from the gauge on the plug at the sender and get 24 volts with it unplugged. I can look at a gauge tomorrow and tell you which post is which.

Are you grounding your panel while doing all of this? A2 panels had a ground wire to the harness but A1 panels were only grounded by the screws that hold them in so when working on it out of the the dash you need to ground it to the dash.

[Hambone]

This is looking at the back of the panel, #6 is harness #27, #5 is harness #36.

photo (92).JPG

[svramselaar]

hi

look at pedros,cz the manual TM 9-2320-218-20
page 2- 75 til 2- 82
there is all for the gauges

wire 27 is the hot wire from the contact trow a fuse

george

[Sundawg3]

Thanks for the prints guys. I also looked at the diagrams on TM_9-2320-218-20 as I was told. I believe the wires, on mine, are connected backwards as to the prints. I should have another gauge in the morning and will install with troubleshooting as you all have suggested. Let you know then!!

[Sundawg3]

Two used gauges, new sender, new gauge, rang out the wires multiple times, cleaned connectors, finally ordered another sender. Looks like the first new sender I ordered was bad out of the bag. Installed the second new sender with the new gauge and it works perfect.

[ODRotorHead]

Alert - - - New Guy Post - - - Proceed with Caution.

I've had a lot of electrical problems with my new-to-me A2 and got frustrated with all of the blurry A2 electrical diagrams. I spent a little time and worked up my own version. I'm reluctant to share it because I'm not certain it's perfect. I'll share this "beta" version in the hope that others will take a close look at it, identify any mistakes, and let me know how I can improve it. If that works out, I'll make the necessary corrections and "reissue" the diagram with a new number/date.

IMPORTANT NOTE: THIS DIAGRAM IS BASED ON THE ORIGINAL, BUT IT IS NOT THE ORIGINAL A2 ELECTRICAL DIAGRAM. THERE MAY BE ERRORS.


REMOVED - UPDATED DIAGRAM MOVED TO NEW SECTION


NOTE: NEW VERSION. Someone was kind enough to send a legible copy of the TM 9-2320-218-20-1-2 (MAY 1982) Electrical System Wiring Diagram. This version (006D - 16 JAN 24) is an update that approximates the most current TM diagram that I have available. The .jpg file size is 12.1 MB.

I tried to spread out the lines to make it easier to read and I modified some of the figures for the same reason. It's been more than six months since I last worked on this, so my recollection is getting a little fuzzy. I seem to remember that I found some mistakes on the original diagram that had to do with the brake/turn signal/running lights. It's possible that I misinterpreted the diagram and the original is more correct. Let me know.

Please let me know if there's anything at all that I can do to make this diagram better. If it's too confusing and creates more problems than it solves, let me know right away and I'll delete this post. I don't want a bad diagram to get out into the "wild."

Mark

[rickf]

EXCELLENT!!!
This is something that is sorely needed for people that are not used to staring at wiring diagrams. I know you sent me this a while ago and I thought I went over the wiring numbers back then but I will go over them again this evening once I warm up, been outside all afternoon. Looks right from a quick lookover though.

For those that don't know, if you click on it it will enlarge, if you click again it will REALLY enlarge for looking at details like the turn signal and light switches.

[ODRotorHead]

The diagram's just for fun but the wire numbering document (.docx) may be useful . . .

REMOVED - INFORMATION MOVED TO POST TITLED Miscellaneous Diagrams and Illustrations.

[ODRotorHead]

While working on my instrument cluster I copied the illustration in the -20-1-1 and used it to sort out the wiring. Near as I can tell, the item numbers and circuit numbers (wire numbers) listed on page 5-144 are reversed for the Fuel Quantity, Engine Temperature, and Engine Oil Pressure gauges.

I reworked the illustration to get rid of the item numbers and substituted the wire numbers for each gauge connection:


REMOVED - INFORMATION MOVED TO POST TITLED Miscellaneous Diagrams and Illustrations.


If I got any of this wrong, please let me know right away and I'll make the necessary corrections.

* Illustration modified as requested (19 Jan 24).

[svramselaar]

hi
you are almost correct only the wire`s 28-33-36 are not together bud the sensors wire`s

look at the book link below page`s 2.75 till 2.81 all aboud the instruments there

http://www.pedros.cz/M151/TM_9-2320-218-20.pdf

all 27 and 27 B wire`s hot at contact on
wire 28 to sensor fuel
wire 33 to sensor temp
wire 36 to sensor oil

the mounting brackets from the meters must have a clean surface to get ground from the instrument panel

[ODRotorHead]

Thank you for the feedback.

You are correct that wires 28, 33, and 36 "are not together." I apologize for using a short hand expression (term) on the diagram that wasn't clear. The rubber socket/plug shells for wires 28, 33, and 36 have raised ribs that run parallel to the long axis of the fittings. If you're reaching in behind the panel to make connections, feeling for the ribs on the connectors may help avoid making the wrong connections. Ribbed socket 28 goes to ribbed plug 28, etc. I'll change the verbiage and try to make it more clear.

I'll change it to "Connect ribbed sockets (28, 33, 36) to ribbed gauge plugs." Let me know if that's okay. If not, I'll delete it. It's just a tip.

Thank you for the -20 reference. All good information. You may have already noticed that Figure 2-38, Page 2-76 of that -20 version (SEP 71) shows all four gauges reversed - left to right. A later -20 version (MAY 82) has the wire numbers in the text reversed. Lots of errors that just add to the confusion.

From what I've read, most of the instrument grounding problems stem from the panel not being grounded to the dash. I don't know the history, but later versions have a fixed panel ground just below the Hi Beam indicator light that plugs into the harness [57]. I can't find the reference, but I've read a suggestion (PS Magazine?) that operators of earlier versions drill a small hole in the panel in that same location, and install a wire that grounds the panel to the vehicle frame. Assuming clean threads, a star washer under the head of one of the panel mounting screws will probably do just as well.

Thanks again.

Mark

[Mark]

I installed a flat grounding wire from the gauge panel to the transmission.