Documentation standard: conditions below were recorded as found and measured against published specifications where they exist, with photographs taken before components were disturbed where applicable. Information received secondhand is identified as reported. This document records physical findings and measurements; it does not attribute any finding to any party.
Customer: “The whole dash goes dead. Gauges, radio, all of it, for a few seconds, then it comes back. It does it after my husband's been driving it.” Comes and goes. Started about a month ago.
No prior work on this concern.
Memory driver seat. The seat runs to her position when she gets in after him.
Diagnostic codes on record: U0155 (history, 9 occurrences), U0184 (history, 9 occurrences).
Published diagnostic procedure was run and terminated without resolution — U0155 Lost Communication With Instrument Panel Cluster (ends at replacing the cluster; not followed, the radio drops at the same moment).
13 conditions considered · 8 ruled out by test · 1 found · 2 tested with a reading · 2 not examined
| # | CONDITION | DISPOSITION | ON WHAT EVIDENCE |
|---|---|---|---|
| 1 | Cluster failed internally | RULED OUT | the radio drops at the same instant, same 9 counts |
| 2 | Radio failed internally | RULED OUT | the cluster drops with it |
| 3 | Battery or charging supply | RULED OUT | 12.6 V engine off, 14.3 V running |
| 4 | Cluster power feed | RULED OUT | 12.4 V at the cluster connector, key on, under load |
| 5 | Cluster ground | RULED OUT | 0.03 V drop, lights on |
| 6 | Termination missing or open | RULED OUT | 60 Ω across CAN-IHS (+) and (−), battery off |
| 7 | (+) and (−) shorted to each other | RULED OUT | cleared by the same 60 Ω reading |
| 8 | Open in the backbone | RULED OUT | cleared by the same 60 Ω reading |
| 9 | Water in the left kick-panel connector | TESTED | water and green corrosion on the network pins; cleaned and sealed, the dash died again on the next seat move |
| 10 | CAN-IHS (+) to ground, harness at rest | TESTED | 2.6 V key on, open with the battery off |
| 11 | CAN-IHS (+) pinched in the driver seat track | FOUND HERE | 0.3 Ω to ground with the seat full forward, open with it back; MIN 0.0 V as the seat ran forward |
| 12 | A module holding the network down | NOT EXAMINED | not reached before the fault was found |
| 13 | Gateway | NOT EXAMINED | not reached before the fault was found |
Two modules dropped at the same instant, the same number of times, so the fault is in what they share: the network. Termination read 60 Ω, so both ends and the pair were whole at rest. The kick-panel connector had water in it, but the dash died again after it was cleaned. It explained something. It did not explain everything. The customer said it does it after her husband drives. What a different driver changes is the seat, so the seat was run with the meter on the network wire.
Root cause — confirmed: CAN-IHS (+) wire to the memory seat module pinched in the driver seat track. The insulation was cut through, and the wire shorted to the seat frame whenever the seat ran forward, pulling the whole network down. Repaired the wire with a soldered splice and adhesive heat-shrink, kept the pair twisted, and rerouted and clipped the harness clear of the track.
Verification: Seat run end to end ten times, both memory positions, meter on MIN/MAX: MIN 2.4 V, no dropout. (+) to ground with the battery off and the seat full forward: open. 14-mile road test with two driver changes and memory recalls: no dropout. Codes cleared; none returned.
Durability: 30 days elapsed with no comeback — proven under time.
1. Battery, engine off / running. Measured: 12.6 V / 14.3 V. Expected / specification: 12.4 V or more / 13.8 to 14.7 V. WITHIN EXPECTATION.
2. Cluster feed at the connector, key on, under load. Measured: 12.4 V. Expected / specification: within 0.5 V of battery. WITHIN EXPECTATION.
3. Cluster ground, lights on. Measured: 0.03 V drop. Expected / specification: under 0.1 V. WITHIN EXPECTATION.
4. CAN-IHS (+) to (−), battery off. Measured: 60 Ω. Expected / specification: 60 Ω (two 120 Ω in parallel). WITHIN EXPECTATION.
5. CAN-IHS (+) / (−) to ground, key on, at rest. Measured: 2.6 V / 2.4 V. Expected / specification: about 2.5 V each at rest. WITHIN EXPECTATION.
6. Kick-panel connector cleaned, MIN/MAX on (+), seat run forward. Measured: MIN 0.0 V; dash dropped out. Expected / specification: holds about 2.5 V. OUT OF EXPECTATION.
7. CAN-IHS (+) to ground, battery off, seat full forward. Measured: 0.3 Ω. Expected / specification: open. OUT OF EXPECTATION.
8. Same point, seat full back. Measured: open. Expected / specification: open. WITHIN EXPECTATION.
9. After the repair, battery off, seat full forward. Measured: open. Expected / specification: open. WITHIN EXPECTATION.
10. After the repair, MIN/MAX on (+), ten seat runs. Measured: MIN 2.4 V, no dropout. Expected / specification: holds, no dropout. WITHIN EXPECTATION.
11. Road test, 14 miles, two driver changes. Measured: no dropout, no codes. Expected / specification: no dropout, no codes. WITHIN EXPECTATION.
This record does not attribute any finding to any person or organization. It records what was measured, what was ruled out, and on what evidence.
The following conditions were on the suspect list and were not examined — the fault was found before the walk reached them. They are neither excluded nor implicated:
If it returns: meter on CAN-IHS (+) and run the seat first. The splice is under the driver seat.
• U0155 on its own points at the cluster, and the published procedure ends at replacing it. The radio dropped at the same instant with the same count, so it was not followed.
• The left kick-panel connector had water in it and green corrosion on the network pins. Cleaned and sealed, the dash worked on the test drive, then died again the next time the seat moved. It explained something. It did not explain everything.
• "Only after my husband drives it" sounds like a driving habit. What a different driver changes is the seat position.
No photographs attached to this case record.
Findings summary · 2012 Ram 2500 Mega Cab 5.7L · Network / communication · Prepared by Dale · Measurements as recorded at the time of inspection