Romain

I can't thank you enough guys. I ordered a new ICM. It will take a week. I'll report back after getting and installing it.

So, I direct wired the Tach and ZERO. I have a tach from a '91-'96(?) cluster and hooked it up. The electronics in the cluster are all different but it has the same 3 inputs. It hovered slightly above zero at idle and idling around 3-4K RPM, that gauge went up to about 1K RPM. The reading is not right and it from a post-renix MJ. Is the new tach I got bad do we think?

I walked through some tests this morning. There IS continuity between C213_C and C203_12. The IS NOT continuity between either of them and ground. Hooking up to D1_1, I can read voltage while running and using the REM2 to read the RPM, I get: o Idle @ ~800RPM gives 1.11 volts o ~2,000 RPM reads 1.23 volts o ~3,000 RPM reads 1.34 volts Next would be to hardwire the Tach to D1_1? There are three connectors on the Tach, 1st says Ignition (I'm guessing 12v), 2nd says ground, 3rd is unlabeled. I don't want to blow this Tach if it's good, but I'm guessing I'd wire 1st to battery +, 2nd to ground, 3rd to D1_1 ??? You guys have been great so far. I'm learning a lot.

Thanks for the technical support. The electrical system is certainly my weak spot. Ωhm, C213 (found it) to C203 is a longer run than my multi-meter leads. I'll have to improvise a longer cable to test the continuity. scaleless, I'm not sure where D1 is. I don't see any obvious burnt wires. Had that before on a '77 FIAT Spider after an engine replacement and, yes, that was a real mess. Nothing like that here. I'll report back after testing. Thanks again.

Well, I'm really confused now. I pulled a full cluster to upgrade the original dummy cluster. The original salvage tachometer's board broke when I disassembled it for cleaning. The screw was rusted into the circuit board and the board broke before the screw let go. I tried a repair that was cosmetically ugly but seemed OK. When I plugged up the full cluster, everything worked fine... except... the Tach gave readings for a few seconds and went to zero. A resistor clearly burned out on it. Replacing the oil pressure and temperature sensors with senders went smoothly and everything else is perfect. I got a new cluster from 87MJTIM, good man, and the Tach looks perfect. I put it in the cluster and plugged it up and... nothing. The Tach's board looks perfect. I've cleaned the copper contact sheet on the back side and even tried a different one. All the fuses are good, all the contacts are clean and making contact, but there is no tach activity at all. Any idea where to look next? If all else fails, I'm going to put a 4" round photograph of a nature scene over the Tach and call it at that. LOL My MJ is an automatic, but everything I've read says that doesn't matter. The Renix Engine Monitor shows I have RPM so the Renix computer is reading it OK. It's just not getting to that gauge for some reason I've yet to determine.

1988 Jeep Comanche Pioneer 4.0L Automatic Transmission 4x4 Short Bed Current Location: Germantown, MD It was repainted and refurbished in 2005 and entered into car shows. Original Purchase: Delaware. Has been in the Delaware/Maryland area her whole life Status: Running Strong - She's been garage kept and has NO RUST ANYWHERE Notes: 2" Lift, 30" Tires For some reason, a previous owner changed only the rear from the factory 3.55 to 4.10, leaving the 3.55 in the front. I've set the rear back to 3.55 and it gets better economy and better highway performance. It was obviously driven in 4WD with the 3.55 & 4.10 configuration, causing unknown damage to the transfer case, but definite shake, rattles and rolls. It's going to be rebuilt soon by The Gear Shop in Baltimore.

In trying to upgrade my gauge cluster to the full gauges, I pulled a cluster from a Cherokee and everything worked except the Tach which burned out when I put power to it. I'm wondering if anybody has an extra Renix Tach I can pick up. Thanks Romain Tweedy