Divide and conquer the Blinking Odometer

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Question. Does anyone have their mileage indicator flashing?? If so, how to fix it?

This is a common question among Aktiv owners so we've added a hack to help. The owner can't usually fix the blinking but the owner must determine if they need to drive to the RAM dealer or Hymer dealer to have it fixed. The owner must also convince the dealer it's their problem to fix so they don't send you home with a blinking odometer. Knowing a little about your Aktiv's CAN bus will help. Don't worry, if you don't understand this primer, you'll do fine.

CAN Bus Primer

A RAM ProMaster odometer blinks to indicate something is wrong on the Controller Area Network (CAN) bus. The fault could be the original equipment manufacturer (OEM) engine electronics, the OEM radio, a cable or Hymer electronics.

The CAN bus works like a well-run meeting where every electronic box waits for its turn to talk. Your Aktiv's CAN bus even has an On-Board Diagnostic (OBD) connector that lets the dealer connect a computer. The computer joins the meeting to learn every box's health and history.

Figure 1 shows six RAM OEM electronics boxes on a single shared bus - the meeting room. In the Aktiv, one of these boxes is the OEM radio. Another is a controller in the steering wheel that sends messages to the radio when the volume button is pushed. The figure also shows the OBD connector for the dealer technician's diagnostic computer.

Hymer added iDat electronics to the CAN bus so VoltStart could request engine starts and stops. Federal regulations require Hymer make their electronics pluggable so the ProMaster could be returned to OEM condition if needed. Figure 2 shows how Hymer did this. Hymer added a cable with a red connector that plugged into the ProMaster's black OEM OBD connector. That cable added iDat and a replacement OBD connector for the dealer's diagnostic computer. With this cabling, the RAM dealer's diagnostic computer can now talk to the OEM electronics and the RV dealer's computer can talk to the Hymer electronics. BTW: RV dealers may not own the computer so they just replace the cable and iDat to fix Hymer faults.

Unfortunately the CAN bus may fail to work due to software misconfiguration or a broken electronics box. The software or broken box can even stop the dealer's computer from diagnosing what is broken. Bus failure is rare but it causes technicians to lose confidence when diagnosing systems with someone else's equipment. The RAM dealer may blame the Hymer equipment. The Hymer dealer may blame the RAM equipment. This is just human nature but leaves you stuck in the middle. You can stop the finger-pointing in 15 minutes.

Divide and Conquer the Blinking Odometer

Tools:

• Phillips screw driver
• Wire cutter (don't worry, no wires are cut)

Parts:

• One 5" cable tie

Instructions:

You don't need to understand the primer to determine if your Aktiv needs a RAM or Hymer dealer. These steps apply to Aktivs with the OEM radio (not Sony). The instructions may apply to Sony but we have no experience with that installation.

Step 1) Make a list of anything you know is not working on the CAM bus. Odometer blinking? Rear speakers? Steering wheel radio controls? VoltStart?

Step 2) Turn off the ProMaster and cabin.

Step 3) Using the screwdriver, remove the fuse box cover located at the drivers left knee.

Step 4) Touch the metal bolt head at the bottom of the fuse box to discharge any static electricity.

Step 5) Find the cable with the red connector tucked behind the dash (see Picture 1).

6) Carefully cut the cable tie that is holding the black and red connectors together. Please don't cut any wires.

7) Disconnect the red connector from the black connector and hang the two cables out of the dash (see Picture 2). BTW: Picture 2 also shows the OBD connector that dealers normally use to fix your Aktiv.

8) Start the ProMaster without touching the exposed wires and connectors.

9) Make a list of any ProMaster equipment not working on the CAM bus. Odometer blinking? Rear speakers? Steering wheel radio controls?

10) Turn off the ProMaster.

11) Touch the bolt. Reconnect the red connector and black connector. Secure the connectors with a cable tie as before. Tuck the cable back in. Install the fuse box cover.

What to do next

1) Go to an authorized ProMaster dealer if when the cable was disconnected: the odometer blinked, rear speakers didn't work, or the steering wheel controls didn't work. Go to step 2 if everything works. Tell the dealer about the radio and control problem, but don't bother them with VoltStart since that isn't their equipment. You might suggest that other people have had this problem because Hymer mis-configured the radio or proxy. SUIET's ProMaster dealer would not work on the problem until we re-disconnected the red and black connectors. The technician then connected his equipment to the black connector hanging out of the dash and fixed the problem. The dealer charged about $300, we emailed a picture of the bill to Hymer, and they refunded. Before leaving the dealer we confirmed the odometer was not blinking and all radio controls worked after the repair. We then followed the previous directions and reconnected the red and black connectors. SUIET's odometer continued to work. Yours may start blinking again. Read on.

2) Go to the Hymer dealer if the odometer only blinks when the red connector is connected. Also go to Hymer if the odometer doesn't blink when the red connector is disconnected and VoltStart doesn't work. The problem must be in the Hymer cable or electronics, and the Hymer dealer must repair.

Good Luck