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AC0QR 05-30-2011 09:15 PM

DIY Cruise Control Dash Light Fix
Background Info: The 1998 TJ I got a few weeks ago came with factory cruise control, which functions properly. However, the dash light did not light up to indicate CC was on. I replaced the bulb, thinking it was burned out, but that did not fix the problem...

Summary: I dug deeper and found that my instrument cluster did not have the circuitry required to light the bulb. This writeup explains what I did to swap the circuitry from the shift light over to the cruise control light. The shift light no longer works (it was annoying anyway), but the CC light does. Victory!

This procedure may work for those who have DIY installed cruise control into their Jeep but don't have an instrument cluster which supports it. I have no idea why mine had factory CC but no dash light. This also may be useful info for people who are looking to put their own 'custom' dash lights in.

Required Tools: Phillips screwdriver, fine-tipped soldering iron, solder, desoldering-wick, LOTS of patience. Optional: Magnifying glass, tweezers, even more patience.

Required Materials*: Replacement dash bulbs if any of yours are burned out

(* I moved the shift light circuitry in order to make the CC light work. If you want both to work, you'll need a BC373 transistor (NPN Darlington type), a 47k 0603-size resistor, a 10K 0603-size resistor, and a 1A rectifier diode)

Technical Level: Moderate to Difficult. Very fine soldering/desoldering required.

Technical Description: Basically the way the instrument cluster works is that for each dash light, there is a transistor, a diode, and two surface-mount (read "tiny") resistors which connect it to the processor on the board. You will desolder the components which connect the shift-light, and move them to the spaces which are supposed to connect the cruise control light, but were never soldered in at the factory because your Jeep didn't come with that option!

AC0QR 05-30-2011 09:16 PM

Step 0 (Prep): Remove your instrument cluster. It's extremely easy. Take out 11 or so screws and it comes right out. There's a writeup how to do it here:

TJ White Gauge Overlays - 1

AC0QR 05-30-2011 09:18 PM

Step 1
2 Attachment(s)
Step 1: (Removing the circuit board)

Remove the plastic panel which protects the circuit board on the back of the cluster. Carefully lift the tabs up on the side and pull the panel off.

I annotated the pictures below to show which components to move in the next step. However, you'll need to desolder them from the back side of the board. Take ALL the screws out of the board (there are 24 for the gauges plus 4 for the connectors), and carefully remove it so you can desolder from the back side.

AC0QR 05-30-2011 09:19 PM

Step 2
2 Attachment(s)
Step 2: Now that the board is removed, you will desolder the components listed below. Refer to the attached pictures which show the exact locations of the components.

Note: All of the 'unused' holes which you will be putting components into will have solder in them and need to be desoldered as well.

1.) Desolder the diode which connects to the shift light, and solder it into the holes next to the right side black connector. NOTE: the "stripe" on the diode MUST point toward the top of the board, or else it won't work!

2.) Desolder the bottom-most transistor in the center of the board, and solder it into the top-most position (the bottom position controls the shift light and yes you guessed it the top position controls the cruise control light).

The next step shows the components to move on the BACK side of the board.

AC0QR 05-30-2011 09:21 PM

Step 3
1 Attachment(s)
Step 3: I have annotated the pictures below to show the locations of the 2 resistors you need to move on the BACK SIDE of the board.

1.) There are 2 tiny surface mount resistors on the reverse side of the board next to each transistor. Move them from the bottom-most positions, to the top-most positions, just like you did with the transistor. The resistor on the left needs to stay on the left, etc, but unlike the diode, resistors are not polarized so you can solder them in facing either direction.

This step is the hardest as the resistors are so small. Do this over a large white towel so if they drop you can find them easily. You may want to use tweezers to put them in place, and a 2nd person to hold them there while you solder.

2.) Put a bulb in the Cruise Control light space! (I swapped the shift bulb over to the cruise because the shift light won't work anymore anyway)

AC0QR 05-30-2011 09:22 PM

Step 4
1 Attachment(s)
Step 4: Put everything back together and try it out! Once you get the instrument cluster itself put together, I recommend only 'tacking' it in with 2 screws to the dash, so if it doesn't work on the first try you don't have to remove everything to get it out again.

FYI, my cruise control dash light turns on for a moment at startup (along with all the other dash lights), and also turns on when cruise control is turned on (but not necessarily 'set'). Other model-years may operate differently.


wranglernut 05-30-2011 11:29 PM

Awesome write-up... Just wanted to comment and say thanks! This is one of those threads that no one will respond to until one day you've forgotten about it and someone will write on how great and helpful it was!
Keep the write-ups coming!

AC0QR 05-31-2011 01:14 AM

Thanks! I shall quietly wait for that day...

But maybe in the meantime I'll get a mod to link this in the DIY sticky thread.

toby_tyler 05-31-2011 05:19 PM

Very nice write up. I have cruise but im almost positive there isn't a spot for a light. Unless its just hidden, you can see all the others even without them lighting up in the sun usually.

hcarlgolden 07-30-2011 08:37 PM

nice write up look forward to more like these.

hobiecat 01-31-2014 08:02 PM

Great write-up. Once I get my cluster problem slammed I'll probably give it a shot.

Lakeman1 04-20-2014 07:09 AM

My 4 WD light doesn't light, hopefully its the bulb, will give this a try. Thanks

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