Instrument (guage) voltage regulator.

[DAYLEY/CHALLENGER]

Ok, I have been not getting any reading on oil and temp guages since I have had my engine where I can run it some.  I have read here somewhere that the IVR could be the problem. I pulled the dash out again tonight to get to the thing and  after pulling it off the back of the panel I checked the continuity from all posts and there was continuity on all contact points. This doesn't seem quite right to me so I am asking the question if this is correct.  I also checked the continuity on the  temp guage and it read good. The oil pressure read the same so I think the guages are ok. I found that Advance Auto has a new  IVR for  $21.00.  I just need to know it this is the right step to take.  Thanks, David

[Devil]

You might want to read this.  I think it might help.

http://allpar.com/history/mopar/electrical2.html

Ryan

[FY1Cuda]

I have a loose instrument cluster and so I checked the IVR with an ohmmeter and got .8 ohms (w/ the capacitor disconnected).  The thing is probably just a resistor in a can, so if you're getting continuity, I'd guess it's still working.  You could check the black wire that goes to the voltage limiter by seeing if you have continuity (zero ohms) between it and the black wire side of the flasher plug.  They connect to the cluster of mainly black wires that are all spliced together in the harness. Lastly, if the capacitor is bad and shorting, then I imagine that would mess things up.  My basic ohmmeter shows infinite resistance (no continuity) when I check between the capacitor plug (disconnected) and the capacitor body or mounting.

[PlumCrazy]

Ok, I have been not getting any reading on oil and temp guages since I have had my engine where I can run it some.  I have read here somewhere that the IVR could be the problem. I pulled the dash out again tonight to get to the thing and  after pulling it off the back of the panel I checked the continuity from all posts and there was continuity on all contact points. This doesn't seem quite right to me so I am asking the question if this is correct.  I also checked the continuity on the  temp guage and it read good. The oil pressure read the same so I think the guages are ok. I found that Advance Auto has a new  IVR for  $21.00.  I just need to know it this is the right step to take.  Thanks, David

The VR shown is the correct one, make sure the one you get looks exactly the same.

[PlumCrazy]

You might want to read this.  I think it might help.

http://allpar.com/history/mopar/electrical2.html

Ryan

The heat generated by that chip is excessive, check out the size of the heatsink used on a sister chip of the chip used in the article plus it also has a fan cooling it.  The inside of this unit gets no where near as hot as the area behind the dash can get.

[Bullitt-]

 David, You did not mention the fuel guage, if it is working this is not the problem.
Simple test is ground the wire that goes to either of the sending units & that guage should peg.

[DAYLEY/CHALLENGER]

Hey Wade.  The reason I didn't say anything about the fuel guage is that I haven't any wiring back  in  place to the rear of the car yet. So I am still not  sure about the IVR.  Now I did a check on the IVR and it shows continuity when I touch the  tester to the Ign post to the case. Same thing from the other post to the case. and same thing post to post.  To me this shows the whole thing is grounded out. But I don't know if this is correct or not.  The Advance part shows different post set up.  Three individual posts where this one had a double and a single. Pulling the dash out just to check this thing is a pain. I am going to rig up a tester for the guages since I know that 12 volts will fry them and try to determine if they are still good.  They did have continuity between the posts on them.  Since I have the dash  out I may as well try to trace all the wires and see if there is any more problems and identify some loose ends too. 

[Bullitt-]

David, You can get away with using 12volts to test the gauges just don't leave it connected for more than a couple of seconds or use a 6V drycell to keep things simple.
  Testing the IVR the body is the ground with power in the single post & is a short thru the heater that is used to cycle the voltage on & off .   Connected to 12volts continuity from input to output should cycle every few seconds.
   I think the 2 prong replacement IVR's are for A-body but there are 3-prongs on the market. These things are a crummy design & can fail in the closed position which results in burnt out gauges.  The do-it yourself solid state regulator (described at Allpar)  I'm told this can be made for about $6.00 in components from a electronics vendor, I would suggest building it on breadboard to keep it isolated. 

[DAYLEY/CHALLENGER]

OK this is the results of tonights efforts. I tested the temp,oil, and fuel guages with the 12 volt touch method.  Each guage showed responce with needle movement.  So I tested the IVR with the black wire to the body and the red wire to the double terminal posts and the meter hooked to the red double terminal and black to the single post.  I was able to see the voltage changing from around 6 volts to 10 volts and it did this steadily. SO I think the guages and the IVR are all good.  Now I am checking my wiring to see if I have an open circuit somewhere. Man are there a lot of wires in this thing.  I have somewhat of a diagram but it is still difficult as the previous owner had done some rewiring too.

[DAYLEY/CHALLENGER]

Now I reinstalled the dash today. Still no reading on the oil and temp guages.  When I was testing the guages I also checked the fuel gauge. It worked too for the test. In looking at the wiring from the IVR, all the wiring is in series going to the guages. Could it be that I have to have the fuel guage hooked up too in order for all the guages to work?  Guess I am shooting in the dark riight now.   

[Lunchbox]

In looking at the wiring from the IVR, all the wiring is in series going to the guages. Could it be that I have to have the fuel guage hooked up too in order for all the guages to work?  Guess I am shooting in the dark riight now.   

Dayley I don't think it is in series it looks to be in parallel. If it was in series it would go to one gauge's + terminal then the - terminal on the same gauge would go to a + terminal on another guage and so on and so forth. Have you checked the lead wire from the IVR to the guages in each connection?


Lunch

[DAYLEY/CHALLENGER]

 :bricks1:Rats..........I didn't chect that.  In looking at my wiring , it appears that each guage has a hot wire going to it and a lead from the IVR that leapfrogs to all 3 guages. Any way.........its going Monday to paint and I will just have to deal with it after that.

[Bullitt-]

Simple test is ground the wire that goes to either of the sending units & that guage should peg.

Did you ever try this?

[DAYLEY/CHALLENGER]

Hey Wade. I did try the ground test before I pulled the dash.  I haven't since then . I will have my boys here today and will try that method again.  What do you think about the fuel guage not being in the loop yet?  Would this be a problem?  And I replaced the temp and oil sending unit at the same time (month ago).  So I don't think it is the units themselves.  I tried the 3 speed wiper motor, works, the windshield washer pump, works, I haven't hooked up any lights (exterior) and I don't have any dash lights comming on either.  Leads me to believe I still have something unhooked that is effecting all the non working items.  Sometimes something so simple is the hardest to trace.   Thanks to all who have guided me.   

[Bullitt-]

The fuel gauge not being connected would not be an issue.
You have tested the IVR & gauges & they seem to be good.
This would be my approach.
A. With ignition ON check that 12volts is getting to the IVR. With the panel out you may not have a ground for the IVR to operate so provide a temporary ground if needed.
B. Check that voltage is getting to the gauges from the IVR.
C. Ground the sending units wires, the gauges should peg. Be sure the motor block has a good ground.
With each of these steps taken & gauges work the only thing left is the sending units.