Moparts Forums >> Moparts Question and Answer

Pages: 1
Anonymous
Unregistered



1969 Dodge Charger Dash Problem
      #5401846 - Thu Aug 06 2009 06:07 PM

I've got a 69 Charger and have developed gauge issues. A while back my alternator gauge shorted out and thus killed the rest of my gauges. I've since replaced the entire cluster and heres the problem. When you start the car the fuel gauge goes straight to full and stays there and the temp gauge goes straight to hot and stays there. The fuel level in the car isn't full. The oil pressure gauge doesn't work at all. The car has new wiring from headlight to tail light. I tried something today and don't know if its right or wrong. I put a ground wire from the cluster to the frame of the car, still no difference. Also under the hood next to alternator pigtails there's a purple and black wire connected with a ring type connector that looks like it would fit the back of the alternator but my wiring diagram doesn't show it. Can anyone shed some light on this? Thanks

Post Extras: Print Post   Remind Me!   Notify Moderator  
Gusteve
I Love the Unicorn Song!!


Reged: Mar 21 2007
Loc: Flint, MI
Re: 1969 Dodge Charger Dash Problem [Re: ]
      #5401852 - Thu Aug 06 2009 06:14 PM

If you are willing to pull the cluster: Make a thing with two C-Cell batteries and wires on each end and power up each gauge. They should read about 1/2 way. That will at least tell you if the gauges toasted.

If they work, then the next thing might be the voltage regulator on the back of the cluster. Although it might be easier to replace this first since you don't have to completely remove the cluster to do so.

Although - my first guess would be a ground problem, but i sounds like you tested for that already.

If its a new cluster - did you know if the gauges even worked at all? Did you clean up the circuit board and test for continuity on the green connections on the board and make sure they were good (conducted, and not grounded)?

edit - and I'll add that you have to do the continuity tests on the board itself that I described earlier. Also - are you sure the voltage regulator is good?

Edited by Gusteve (Fri Aug 07 2009 05:39 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Anonymous
Unregistered



Re: 1969 Dodge Charger Dash Problem [Re: Gusteve]
      #5401865 - Thu Aug 06 2009 06:20 PM

Can you describe how to make the c battery tester thing in more detail? The little voltage regulator on the cluster is new, not saying it can't be bad though. What about the voltage reg. under the hood?

Post Extras: Print Post   Remind Me!   Notify Moderator  
Anonymous
Unregistered



Re: 1969 Dodge Charger Dash Problem [Re: ]
      #5401896 - Thu Aug 06 2009 06:40 PM

I agree you need to pull the cluster and isolate what is going on. Basically, they way those work is this:

You have a voltage regulator unit, called by various names, "gauge regulator" "dash voltage reducer" it's the long metal box on the rear of the cluster about 3/4" X 2" or so long. It knocks the 12-14V system voltage down to (I forget) 5 or 6 or so to operate the

fuel, oil, and temp gauges Has nothing to do witht the ammeter

So each gauge gets reduced voltage on one terminal, and THE OTHER TERMINAL hooks to a wire that goes directly to each sender, oil, fuel, temp

So this should be fairly easy to trace, you have a diagram? You can use a meter to check out the sender wiring, the battery method above to check out the gauges.

IT IS IMPORTANT not to hook 12V directly to these gauges


Post Extras: Print Post   Remind Me!   Notify Moderator  
Andrewh
super gas


Reged: Feb 17 2003
Re: 1969 Dodge Charger Dash Problem [Re: ]
      #5401900 - Thu Aug 06 2009 06:42 PM

gauges are supposed to have 5 volts applied max.

So 5 volts pushes them to full.

2 cell batteries. AA, or C or D would be 3 volts wired in series, so it should read half way.

New solid state? or New OS type replacement?

If it is solid state, just take a multi meter to it and see what it reads. If it is NOS type new, then take a check light to it and see if it blinks.
If not, it is bad.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Anonymous
Unregistered



Re: 1969 Dodge Charger Dash Problem [Re: Andrewh]
      #5402179 - Thu Aug 06 2009 09:01 PM

Thinks guys I plan on trying again tomorrow, hopefully the gauges test ok. I'll never understand why mopar made such a weird electrical system. I'm not to concerned with the oil and temp gauges since I can just put mechancle gauges in, but the fuel gauge is another story when the car only gets 8-10 miles per gallon LOL Thanks again

Post Extras: Print Post   Remind Me!   Notify Moderator  
Anonymous
Unregistered



Re: 1969 Dodge Charger Dash Problem [Re: ]
      #5403144 - Fri Aug 07 2009 02:40 PM

Ok. I pulled the cluster and did the battery trick. I also took a ohm reading on the circuit board. I hooked the negative lead I attached to the battery to the ground on the regulator. Then, I attached the positive wire to the correct prong for the fuel gauge,then temp gauge, and oil gauge. None of the gauges moved. Did I do this right? I still have the cluster out. I used a meter to get an ohm reading on the circuit board. I tried three times touching the negative probe to the ground on the regulator then the positive to the board. I tried the nagative on each prong of the voltage regulator and got nothing. As Far as the battery test is concerned, doesn't each gauge need the sending unit to tell it what to do? With the cluster out of the car you can't do that. Please let me know if I've done this right or not. At the moment I'm really confused. I'm not sure if I was putting the leads I had on the batterys in the right spot or not. Thanks

Post Extras: Print Post   Remind Me!   Notify Moderator  
Andrewh
super gas


Reged: Feb 17 2003
Re: 1969 Dodge Charger Dash Problem [Re: ]
      #5403234 - Fri Aug 07 2009 03:37 PM

not quite right.
The dash is grounded by the frame not a "ground" lead.
For the battery test, I would run the leads to the back of each gauge not to the circuit board.

That would run it through the regulator, but you stil would not be grounded. so it would not work.

To get power to the whole dash, I would run a ground to the frame of the cluster, then figure out which is the 12 volt pin to the dash and run the postive of the car battery there.

Then take the multi meter to the back of the gauges and see what it reads.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Gusteve
I Love the Unicorn Song!!


Reged: Mar 21 2007
Loc: Flint, MI
Re: 1969 Dodge Charger Dash Problem [Re: Andrewh]
      #5403286 - Fri Aug 07 2009 04:08 PM

Quote:

not quite right.
The dash is grounded by the frame not a "ground" lead.
For the battery test, I would run the leads to the back of each gauge not to the circuit board.

That would run it through the regulator, but you stil would not be grounded. so it would not work.

To get power to the whole dash, I would run a ground to the frame of the cluster, then figure out which is the 12 volt pin to the dash and run the postive of the car battery there.

Then take the multi meter to the back of the gauges and see what it reads.




Right. You need to attach one wire from each end of your two battery thingy to the prongs on the gauge itself. For example - take 2 C cells (or AA or whatever) and tape them together as a long cylinder with the + on one battery connecting to the - on the other. Then tape a wire from the top at +, and tape another wire at the bottom on "-". Then touch the wires to the two prongs on the gauge. It'll take a second or two, and then the gauge will start to rise.

I don't recall whether it matters which wire (+ or -) goes to which prong. Worst case, just look at the circuit board and see which prong is getting power from the regulator, and use that for +.

To answer you direct question - the gauge does not need the sending unit to tell it what to to. The sending unit and the voltage regulator are varying the voltage to the gauge between 0 and 5 volts. By doing the battery thing you are applying 3 volts, so the gauge should go up about half-way.

While you have it out, use your ohm-meter to check all the circuit board connections. i.e. - touch one lead to where the regulator would plug in, and then touch the other end to each spot one of the gauge prongs would go on the circuit board. You can see the path of the circuit by just following the big green stripes on the board. Do this also for the other side of the gauge prong connection, and follow it across the board to make sure you get a good reading all the way around.

--------------------


"It's not easy being sleazy!"

Edited by Gusteve (Fri Aug 07 2009 04:12 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Anonymous
Unregistered



Re: 1969 Dodge Charger Dash Problem [Re: Gusteve]
      #5403374 - Fri Aug 07 2009 05:09 PM

UPDATE!!!!!!!!! The fuel gauge did move as well as the Temp gauge. The oil pressure gauge did not. This brings back the origional problem. When the cluster is in the car and you turn the key to just the on position the fuel gauge still goes to full and the temp gauge still goes all the way to hot and stays there. Is this a sending unit issue? Is their anyway to test a sending unit? I've still got the aftermarket mechanical gauges in the car. All I need to do is hook the plumbing back up no problem. If I can just get the fuel gauge right everything else can go on the back burner, but if anybody has anymore ideas it will be greatly appreciated.
Thanks


Post Extras: Print Post   Remind Me!   Notify Moderator  
Gusteve
I Love the Unicorn Song!!


Reged: Mar 21 2007
Loc: Flint, MI
Re: 1969 Dodge Charger Dash Problem [Re: ]
      #5403396 - Fri Aug 07 2009 05:32 PM

Lets go back to your original problem. Your alternator gauge shorted out, and you thought it took out the rest of your gauges. Did they all work before? I ask this because, as stated in a previous post, your Alternator gauge is not part of the rest of the gauge cluster, from an electrical point of view.

Can you describe what you mean by Alternator gauge shorted out? That has a huge impact on the rest of the wiring for the vehicle, as it can take out some other wires under the dash and in the engine compartment.

In general, the odds that your temp sending unit and gas sending unit died at the same time are pretty slim. Off the top of my head it sounds like a ground issue somewhere.

If you search the forum you'll probably find specific instructions on how to trace down the gas gauge problem. Its a very common question. (Yeah - I know - that's not much help)

edit - I'll add that you really have to do the board continuity test I described previously. Look at the green stripes on the board and you should also be able to figure out the spots where you should NOT have continuity. Test those too.

And - do you know the voltage regulator is good?



--------------------


"It's not easy being sleazy!"

Edited by Gusteve (Fri Aug 07 2009 05:56 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Anonymous
Unregistered



Re: 1969 Dodge Charger Dash Problem [Re: Gusteve]
      #5403431 - Fri Aug 07 2009 05:58 PM

I did buy a new voltage regulator this morning. The one on the car tested bad. I checked the board with the meter and it checked out good. When I had the origional cluster in the car eveadently one of the post that the alternator gauge wires hook to was loose and it burned up the gauge. Smoke poured out and I shut the car down. Since then the cluster was replaced and all of the wiring is nearly new from year one. I looked behind the dash to make sure nothing was burned up but found nothing. I agree with the ground issue I just don't know where to look. I grounded the battery to the body. the cluster to the frame, the motor to the body, and of course the neg. battery cable to the motor. Almost forgot, all gauges did work correctly before the ALT gauge shorted out. When I got the new cluster and installed it, I noticed the ALT gauge worked and the fuel and Temp went all the way to full and Hot and that brings me up to where I am now.

Edited by general440 (Fri Aug 07 2009 06:29 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
pro451bee
mopar addict


Reged: Jan 22 2006
Loc: WA
Re: 1969 Dodge Charger Dash Problem [Re: ]
      #5403978 - Fri Aug 07 2009 10:49 PM

Trace all the gauge sense wires through bulkhead and look for melted wires touching .

Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1



Extra information
5 registered and 55 anonymous users are browsing this forum.

Moderator:  moparts, SanityLost, tboomer, LTDan, 70Cuda383, Hotwheelsjr, not_a_charger, Eric, Al_Alguire 

Print Topic

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled

Rating:
Topic views: 3012

Rate this topic

Jump to

Contact Info | Privacy statement main index

Powered by UBB.threads™ 6.5.2