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Fixing Dodge-Chrysler-Plymouth 3G Minivan Instrument Clusters and HVAC

For the 1996-2000 Plymouth Voyager, Dodge Caravan, Chrysler Town & Country

by Jeremy Schrag

It's a bright, sunny, summer day and you're heading to the beach in your 1997 Dodge Grand Caravan ES or Plymouth Voyager, the a/c on, tunes cranking through the Infinity Acoustic 10 audio system. You stop for gas, then get in, slot the key into the steering column, smile as the starter whirs its strong, proud song, and then... nothing.

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There doesn't seem to be anything wrong. The fuel pump primes, the starter sounds fine, and you just put in a new battery last winter. What could be the problem? Then, you notice it... the odometer isn't displaying anything. Or, it's displaying something, but that something doesn't match up with what should be there. Or, the gearshift indicator has boxes around all positions. Wait, you think, didn't the speedometer go dead on me for a minute there on the highway?

These are a few of the sights when computers get confused. In the late '90s, as cars began to get more and more complex, they relied on several computers, and they all had to talk to each other. If one couldn't figure out what another was trying to tell it, they all crashed.

Chrysler's third generation minivans were no exception to this issue. In fact, they are now rather known for it. All the computers in these vans from the powertrain controller to the body controller to the transmission controller to even the instrument cluster, radio, and heater controls are all connected together over one single computer network called the Chrysler Collision Detection bus, or CCD bus for short. A single pair of wires running throughout the vehicle enables this.

When there are no problems with this computer bus, everything works well, as intended. But if anything should happen to that bus, like a connector pin failing intermittently or a short circuit, the whole thing either crashes and brings the van to a stop at worst, or haunts the wipers or instrument cluster like a poltergeist at best.

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In the above picture, you see the number one reason for all CCD bus failures in Mopar third generation minivans: the instrument cluster. More specifically, your van most likely won't start because of one tiny and utterly avoidable issue: your instrument cluster has bad solder joints.

Yes, a cold solder joint or two just brought down a vehicle that cost tens of thousands of dollars. What is a cold solder joint? The description says it all. It's an electrical connection made by solder that didn't get hot enough when it was applied. Over time these joints weaken and fail, and that's why you're sitting there in a jam-packed parking lot listen to your significant other say, "Come on, honey, let's just call a tow truck and find a motel. Whatever the dealer charges, I guess we'll just have to pay it."

But there is good news. If you own a soldering iron, you can likely have this issue fixed for the cost of nothing but an hour of your time. I'm going to show you how it's done, using this cluster from a 2000 Caravan.

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The first thing you need to do, after disconnecting the battery, is gain access to the cluster. To do so, we need to remove the lower bezel of the dash.

There are five screws that have to come out; I've indicated their rough locations with red arrows above. Two of them are behind the parking brake release handle; don't forget those.

Once all five screws are out, pull the bezel off. It'll be clipped in yet on the right side.

Now, we need to remove this vent on the left side. Take out the red arrowed screw, and just pull the vent right off. It's only clipped on once you get that screw out.

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Now, we'll remove these two red arrowed screws. Don't pull on the cluster bezel yet... there are more screws to remove.

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The panel directly on top of the column has to come off next. Remove this red arrowed screw (above)...

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And then this red arrowed screw (above). You are now free to pop this panel up and off. You may need to move the shift lever to get it out.

Now, remove the green arrowed screw... it's for the cluster bezel itself, but there are still two more screws to pull out before you yank on it.

Don't worry about removing the headlight switch... it comes off with the cluster bezel.

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Once the top column cover is off, we can now access the final two cluster bezel screws. Here's one...

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And here's the other.

The cluster bezel should now be free to remove. It'll be clipped on yet on the right side, so go slowly and pull from the left side until you can get the right unclipped.

Once it's free, reach around back and disconnect the connectors on the backside of the headlight switch. Set the bezel aside.

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Four screws from here hold the cluster inside the dash. Remove these two...

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And then these two. Gently rotate the cluster so that the top comes towards you, maneuver it out of the dash, and unplug the electrical connector. It will help to tilt the steering column down, if you are able.

Now you should be able to remove the cluster.

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Before we look at the problem area, I'll show you the front of the cluster. Red arrows indicate the eight screws that hold the front bezel to the housing. We'll be getting in there later, but you do not need to do this unless you wish to re-work the circuit board for the odometer and gearshift display. This would not affect the CCD bus in any way, shape, or form.

That said, I reckon if I'm already in here, I tend to want to address everything that could possibly fail. If one solder joint has failed, there is a very good chance that there will be more.

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A quick look at the label for this cluster shows a part number of P04685730.

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This is where we will start looking for bad solder joints. First, we must remove the brown insulating cardboard from the back of the cluster. Remove all red arrowed screws, and set the insulator aside.

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Now, we have a pile of screws to remove. I've arrowed them all in red. A blue arrow indicates the connector and ribbon cable that runs to the odometer display board. Disconnect it. It's just friction fit, so no worries about breaking things.

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Remove the cluster mainboard by pulling it up and off. The gauges themselves use friction fit connectors, so the board should just pull right off.

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This is where you get to warm up the soldering iron. Inspect the entire board, and re-solder every joint that looks bad. There is one in particular you should pay attention to... I'll show you that in a minute.

But first, in case you're in need of some light bulb replacing, here's a look at the two kinds used in this cluster: PC74 and PC194. These are permanently married to their bases, so do not try to pull them apart. Instead, head down to the dealer and secure proper replacements.

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Now, this red arrow indicates the one joint above all others you should pay attention to. This is the ground pin for the main electrical connector, and that joint has definitely failed. There are other cold joints in this picture, but this is by far the worst one. This is the joint that is keeping your van from starting. This is the joint causing your cluster to go nuts on the highway.

How did it get this way when most other joints look good? It's really quite simple... take a look at the size of the circuit board trace it's attached to. Rather large, is it not? It's just the way the universe works... the more metal you have, the more heat you have to apply to solder to it. This one circuit board trace is so large that the mostly adequate amount of heat for the other solder joints was not enough for this one. And so, it's failed.

Once you've taken care of this problem child, follow that big trace and re-solder every single other joint attached to it. Then, re-solder every single other pin on that connector. Finally, inspect the rest of the board and make sure the rest of it looks good.

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With the mainboard still off, I'll now show you how to get at the display board. Gently pull the gauges up and out. A black plastic sheet on which you have your gauges is attached to a clear plastic panel... it all comes out as an assembly. There is nothing holding it in right now.

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Remove the three screws arrowed in red.

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Now, we can take a look at the solder joints on this board. All of these look ok to me, so I'll put this cluster back together.

At this time, you might still be sitting there, frustrated. You tried this already, and it didn't work. Your van still won't start, and by golly you'd really appreciate it if the rear wiper would start working again. It's been dead now for a couple years, and you're sick of it.

HVAC Controller Repairs

Fear not, for I am going to explore another area known for causing these issues... the HVAC controller. This isn't as common an issue as the cluster solder problem, and this particular van does not have a problem here, but I've seen this complained about often enough that I'd like to enlighten you folks today.

Make sure the battery is disconnected again, before you start.

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We need to remove the bezel around the radio to which the HVAC controller is attached. Remove the two screws you see above the radio, then pull off the clipped in bezel indicated in red and pull out the two screws hiding behind it.

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This is our area of concern. Enough power runs through this connector that, over time, some of these pins can heat up and go intermittent.

The most problematic of these pins is, once again, the main harness ground. It's the red arrowed one in the above picture. Inspect the connector and pins for damage and discoloration, paying special attention to the blue arrowed pins (the CCD bus connections) and the red and purple (sensor ground) pins. If you find any issues here, you may be able to get by just cleaning the pins. But if the connector is too far gone, you may need to give your local dealer a call. There is actually a repair kit available that goes by the part number 05183485AA. With this in hand, you should be able to get this issue taken care of.

If this still does not take care of the issue, you'll need to investigate further. Inspect all connectors on all parts that interface with the CCD bus, starting with the BCM (body computer), TCM (transmission computer), and PCM (powertrain controller). Head to the library and access their Alldata or Mitchell database, if they have one, so you can check the wiring diagrams to make sure you don't miss anything. And most of all, have lots of patience and faith, for they will be tested by these random electrical gremlins. One wire loose in its connector on these vans is enough to cause countless problems, and you need to check them all until you find the problem. But you will find it, eventually.

The cold solder joints are an extremely common problem, to the point that I'm almost certain that if one of these vans hasn't experienced this issue, there's better than a 75% chance that they will, especially in areas where the temperature likes to fluctuate like my body weight around Christmas time [disclaimer: Jeremy lives in Saskatchewan].

If you own a soldering iron and a Phillips #2 screwdriver, my advice is to tackle this job now, before it gets you in the middle of your vacation or a bad blizzard. An ounce of prevention is better than a pound of the bills you'll get after a mechanic who has no electronics training shotguns part after part at your minivan, hoping that "this time, I'll really get it fixed."

Good luck.

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