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Discussion Starter · #1 ·
Yes another thread about no dash lights. I have read dozens of posts tonight trying to figure why mine went out. I think I know but need a second opinion.

Everything was fine! Should have let well enough alone but I didn't. I did two things to my Jeep today. 1st was the locker mod. Jumpered pins 1 and 4 by way of a switch. That works just fine. Can engage both front and rear in any T-case position. Second was to replace the Sony aftermarket radio with a JVC I had taken out of my truck I sold. The JVC has Bluetooth so I wanted to use it. The Sony didn't have an illumination wire but the JVC did so I hooked it up. All was working great until I turned on my headlights tonight. Just as soon as I turned them on I was looking at my mileage and saw it dim, go bright, dim, go bright, dim, etc.. for about 6 cycles. I then noticed I had no back lighting on my dash. Then about 30 seconds later I could smell something electrical. So I turned around and brought it home, disconnected the battery and started taking stuff off.

So far I know there are no blown fuses. The dim circuitry from the switch seems to be working cause the mileage does have varying levels of dimness as I rotate the switch. I also see a small changing voltage on pin 15 in the black connector as I turn down the dash lights, but I get no voltage at all from pin 6 in the same connector. If I found the right pin out, pin 6 should be dash lights and I am guessing that wire provides voltage to the AC knobs and the gear selector light. Looking at the back of the cluster, the right side smells burnt. And I correct in assuming the new radio (or the illumination wire getting hooked up) fried my cluster. And does the cluster actually provide the power to the rest the illumination items (AC controls, gear selector).

If so, where is a good place to get a cluster? I have looked on eBay and didn't see one. And are all 03 to 06 clusters the same whether it be a Rubicon or not?
 

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:welcome:
The cluster/AC/Gear select/radio illumination is all fed from a circuit within the cluster in later TJs. One fix is to tap the black/yellow wire which feeds the marker lights to the orange illumination wire. That will run the illumination at full brightness.

It's possible since you have a burnt smell that you may be able to identify the component that has failed. If it can be identified, and a replacement located it can be replaced. As I have an early TJ I can't compare my cluster to your one to try and ID the component.

More here regards the wire tap...
http://www.jeepforum.com/forum/f9/another-instrument-cluster-light-problem-1459895/
http://www.jeepforum.com/forum/f9/cluster-gauge-lights-not-working-signal-lights-good-1540071/
 

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Discussion Starter · #3 ·
Thanks Johnny, I was thinking it all feed from the cluster. Must have been that darn radio illumination. I'll try the tap and see if they all come on then start looking for a cluster. Oh and cut that darn wire from the radio free!
 

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I think that black/yellow wire which, as Jonny says is for the marker lights & is fed from pin 9 of the left m-f switch is the "feeding" power to the cluster. It goes through pin C1-5 into the cluster for the "lights on" indicator & I'm pretty sure also would be used to power the "power out" at C2-6 (orange wire) after being regulated through the C2-15 grounding wire (back to the m-f switch).

Does that all sound right, Jonny?

If so, ultimately fuse 1 in the fuse block would be the protecting fuse but at 20a the circuitry in the cluster could definitely fry before reaching 20 amps.
 

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Since the marker lamp feed goes to the cluster I would presume this is used to supply the dimmer circuit. It's possible that the dimmer circuit (aside from the ground) is completely isolated from the rest of the circuit board. I'd like to see the board like the OPs where the circuit has failed, with the burning smell there's a good chance the component could be found even if it has to be compared to a good cluster board to ID the part.
 

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Discussion Starter · #6 ·
Made the jump from Black/Yellow (connector 1 pin 5 on mine) to the orange wire in connector 2 pin 15. I now have lights again. Will just keep a check on eBay for a cluster at a reasonable price. Thanks again for the help!
 

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Discussion Starter · #7 ·
The board didn't have any visible signs of damage but the smell was strongest around IC11. I also traced all the positive leads for the lights to this IC and the right most pin on it. Not sure if that is all thats bad or not but I am going to see if I can find one. The markings on it are.
BUK215
50Y
PHm0222 C4


I placed a switch under the dash so I could turn off the jumper from C1 PIN5 to C2 PIN15 if anything smelled wrong. I drove it for about 30 minutes tonight and at first I did smell some electrical odor but I feel that was the rest of whatever component was failing going on out. The smell stopped but the Lights are Still On!!!
 

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I've googled BUK215 50Y and it is basically a power supply IC. I suspect replacing that would fix the illumination issue.

It's a surface mount device so a hot air solder gun is much better than a normal soldering iron for replacing it. I'm not sure how easy it would be to get one of those ICs in an electronics store over there but they are available for $10 on ebay.com. I have a gas fired soldering iron with hot air tip and have replaced a similar IC on a Renault cluster that had lost power, so if it were me, I'd replace the IC.

The pin outs from left to right are ground, input, battery, status, load. Not sure about the status connection but the others should be connected to ground, dimmer signal from headlamp switch, marker lamp supply, and the output to the lamps (which you have traced to that pin).
 

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If you decide to do this be sure to post results & maybe some photos. There have been a few posts with this sort of problem & finding a solution without replacing the cluster would be great.
 

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Discussion Starter · #11 ·
OK got the DVM out and did some checking on the IC11 pins.

Pin 1 is ground
Pin 2 varies from 1.2 to just over 4 volts when rotating the dimmer.
Pin 3 which is also the top tab that is soldered down is suppose to have 12 volts when the light switch is turned on. But there is nothing!
Pin 4 nothing
Pin 5 output to lights has nothing, but that is because the top tab which is internally connected to pin 3 has no voltage.

I jumped 12 volts to pin 3 and what do ya know. The dash lights work like they are suppose to. Dimmable! Now I need to trace out where the 12 volts is suppose to come from and see what component is stopping it. Looks like IC11 is OK. At least it is on my board.

If anybody else wants to help find the next component in the line feel free to let know know as well. A schematic of the cluster board would be awesome!
 

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Discussion Starter · #12 ·
Anybody know how to remove the board from the cluster. I'm pretty sure there is going to be more circuitry or at least traces on the back. I need to see what is connected to CL7.
 

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Discussion Starter · #13 ·
OK so I couldn't find any videos or write-ups saying how to get the cluster apart so I just started pulling pieces off. Most important thing I figured out; You DO NOT have pull the needles off to repair the board! In fact the front cover doesn't need to come off at all. To get the circuit board out all you have to do is remove the 24 Phillips head screws. These screws are making the connections to the stepper motors. The motors will stay with the rest of the housing. What I found was connector 1 pin 15 (black wire with yellow stripe) is directly connected to IC11 on the top tab. This wire provides the IC with 12 volts when the light switch is turned on. Here's a pin-out of IC11. It is variable voltage regulator.

Pin 1 = Ground
Pin 2 = Variable voltage from 1.2 volts to 4 volts based on dimmer position
Pin 3 = Input voltage internally connected to the top tab of the IC
Pin 4 = Status. not sure if it's doing anything on this cluster
Pin 5 = Output voltage to all Dash lights (Via the Orange wire from connector 2)

So on the back of the clusters circuit board the trace going from Connector 1 pin 5 to IC11 Pin3 (top tab) was fried. Burnt in to actually. So I soldered the trace back together. I also took a piece of category 5 network cable and added a jumper between those two locations for extra protection. The wire was the perfect size to push threw the holes in the board.

So if you have no dash lights, take your volt meter and check for continuity between those two locations. If there isn't any, then solder in a jumper and enjoy light once more!

My cluster now functions just like it did before I hooked up that darn illumination wire on the aftermarket radio!

So the cost of this repair.... nothing! Sure beats buying a $100+ cluster.
 

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Nice work. Well done tracing an fixing the fault. If others with the same fault have the same failure it will be a simple fix.
I wonder if it might be worth adding an inline fuse to the black/yellow wire so the fuse would fail before the circuit burns out.

Edit:
Earlier TJs had the dash/cluster lamps fed straight from the headlamp switch. The wire from the headlamp switch ran through a 5A fuse behind the glove box. Although the IC that controls the dimmer circuit in later TJs can handle 20A that burnt track may be thin enough to be acting as a fuse during shorts on the orange wire, or high demand from aftermarket radios perhaps. Adding a 5A inline fuse to the black/yellow wire going into the cluster, or the orange wire coming out of it may be a good way to protect the circuit.
 
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