1991 OCC - Highway RPM seems high (1900 at 60mph)

1991 Custom Cruiser (stock). 160,000 miles. Runs great (although idle seems a bit high at 900 rpm in park).

I also have the Climate Control package which I'm trying to use as an alternative RPM display.

I thought it used to read around 1500 when it kicked into overdrive at 60mph.

It is now at 1900 rpm.

I can't for the life of me find the specific instructions on how to display the RPM on the Climate Control display. I've looked and I found lots of stuff for other models, but not mine.

I can press EXT TEMP and OFF and get -00.

I press the up fan button to get to -06. Pressing the EXT TEMP button at this point displays 00.

Does the highway RPM seem too high?

How can I get the RPM display on the Climate Control?

I do not think the OCC climate display can give you the readout of the RM climate display. The display for the RMs may only be in the 94-96 cars as well.

If the tach is off, you may have a tach issue in the cluster. I had a cluster that acted up. I swapped the cluster, and all was good. If you need a cluster, I have a couple on hand.

You should check your rpm with a calibrated external unit to verify the cluster tach. With 3.23 gears, the tach reading is around 1700 at 60 in lockup, and just a little under 1500 at 50 mph. If you have 2.73 gears it will be less. Idle in gear should be about 700. 900 in park is not unusual. Check your grounds at the thermostat housing, and the rear of the heads.

Your tach is fed directly off of the coil.

As always Fred, you are a font of excellent knowledge. Thanks for the info.

Drive at 55mph on flat ground, foot on gas. Note tach reading. Keep foot on gas. Use left foot to very lightly apply brake. Does tach increase? It should, that is the torque converter unlocking. No change? The converter wasn't locked (and you've found your problem).

Thanks for the info! Will do all that is suggested and report back.