Chasing some electrical gremlins. My gauges work almost instantly when I turn the key to accessory but take about 5-10 minutes to start working after I start the car. I replaced the original dash voltage regulator with a new solid state piece and I have the same problem. On a possible related gremlin, car will not fire when cranking but starts the moment I release the key. I quickly checked and I don't have voltage to the start pin in the bulkhead. Any ideas? Possible ignition switch?

Usually when it only starts after you release the key it's a ballast resistor issue, but if you have no voltage at the bulkhead pin it's most likely the ignition switch.

Check at the output of the ignition switch to verify.

If you have voltage there but still not at the BH, could be a flaky bulkhead connection. On the gauges, could be related or a separate issue. resolve the start issue first.
Once that is resolved if the gauges are still acting up, do not forget to check and verify your grounds between the battery, engine, body and dash cluster on the gauges.

Hmm. I thought the opposite. If the car was able to run after releasing the key from start mode, the voltage must pass through the ballast resister to step down the voltage to the coil so the resister must be working, no?

You are correct, getting old sux, lol

Mopar engineers designed a ballast resistor bypass circuit when they switch from 6 Volts to 12Volt sin 1956, the ignition switch has two 12V feeds into the ignition circuits, one to each side of the resistor so it will start quicker with 12V. feeding the coil in the start position and then run on the voltage coming out of the resistor with the key in the run position
You're not the first one to run into this, trust me

Thanks. Anyone want to take a guess at why the gauges take 5-10 minutes to start working?

When you start the car and it is running, quickly take a test light and check the voltage at the temperature sensor stud with the sensor connected. It should be flashing about twice a second at full brilliance. If not, you still have a problem with the IVR or its connections.

I will check that. If it's not flashing initially, could it be a bad circuit board?

Electrical instrument cluster problems can always be caused by a bad circuit board. But I am a firm believer is going after electrical problems in a systematic approach, not shot-gunning this or that with no rhyme nor reason. This is the place to start with temp/fuel/oil pressure (if equipped) gauge problems.

I'll agree but REFER you to EARLIER POSTINGS






So, let me rephrase my earlier response.
ARE these NEW issues that just appeared or have they been there and or getting worse over time?

ASSuming the wiring is stock, in good condition and not butchered up proceed as follows:

I would recommend using DVM for testing vs. a test light. A DVM will become a good firend once you learn how to use them and they are relatively cheap. One can get by with a test light if you pay attention to the bulb brightness.
Voltage and Current are two different things that interact and you need both for a circuit to function.
I would strongly recommend solving the start issue first. I would also recommend leaving everything in the circuit hooked up for the initial test.
If you have voltage at the start terminal of the ignition switch but not at the engine side of the BH, your problem is likely a connection between the two causing a loss of voltage or the ability to pass current.
If you DO NOT have voltage or weak voltage at the start terminal, replace the switch.
You can also Disconnect the bulkhead and repeat the test as something maybe drawing the voltage/ current down. However that's a bit of a long shot as there are only two things active, 1. is the start V to the coil 2. woul d be the starter relay. A 3rd could be power to electronic ignition if so quipped

As stated previously the gauge issue may or may not be related. 1 step at a time starting with the easiest first. In my 50+ years of experience, I would suspect the Ign switch as you say they operate fine in the accessory position. The IVR, circuit board, wiring etc. don't know which position the switch is in, BUT they work in accessory. there MIGHT be a clue there but not necessarily. Welcome to the world of ELECTRONS. they are fussy little SOB's that have driven more than one person to the looney bin.

On a side note: I don't seem to recall the gauges being operational in the accessory position ? maybe another can clarify that as if they are not supposed to be that would add another issue to the quandary

It could be a myriad of things. But checking for voltage at the sensors, oil pressure, temperature, and fuel level tells you three things, 1) the IVR is working, 2) the dash gauge is not burned out, and 3) the wiring through all the components other than the sensor is intact. This is the most direct way to troubleshoot gauges of this era. In this case if it takes 10 minutes for the gauges to respond after an engine start, doing this check immediately after the engine starts will point the way to the next phase of trouble shooting.

TPJ - Lots of good info here. The wire harness is stock except the amp meter bypass that everyone is doing these days (see attached method I chose). In accessory mode (turn key to left) , my fuel gauge starts moving and if warm, so does the temp gauge. I'm heading out for a long needed vacation but will return in a week and report my progress.

Sounds like somehting is cross wired.
According to the FSM the instrument cluster gages get power from wire G5 - which comes from the run terminal on the key switch. In other words, there should be no power to gages with key in accessory.
Since there is also the starting issue, might be worth disconnecting the key switch and testing the continuity is correct in each position.

Good point. I've only owed the car for about 2 months so I'm not exactly sure what's going on beyond the Amp meter bypass which is relatively simple. The gauges behaved the same way before the bypass so not related IMO.

As stated, someone crossed something somewhere and when Bubba's been there it can be a challenge to figure out as he's pretty good at hiding his cr-p. AMHIK.
I would start by pulling the front seat as your likely to have some time under the dash Do keep us posted

Just got back from a trip to Cape Cod and I'm going to roll up my sleeves and solve this mystery this weekend. Fortunately I was in the middle of replacing my carpet so I should have easy access to the harness. I'll report back on my findings.

Keep us posted

Ignition switch is apparently part of the problem. No voltage passing through the IGN 2 lug on the switch (Brown wire to ballast) so I need to replace that. I also hooked up a test tight to the temp sensor lead at the front of the block. When turning the key to ACC, the test light flashes but it doesn't when the key is switched to IGN 1. Looking under the dash, everything appears to be stock and in its proper place with no apparent splices. The IGN1 circuit to the dash eventually starts working after 5-10 minutes so maybe a bad circuit board ground? On a '69 Charger, how is the dash/ circuit board grounder?

Mattax, I traced the G5 wire (referred to as P4 18DBL* on 1969 Charger Wire diagram) and it goes to the brake warning lamp. See attached. Looks like the 12V dash feed comes from the Black Wire node splice, no?