Gauge Cluster self-test?

I'm having issues with my gauges.

1. The temp gauge reads 210* as being the first tick mark (I verified the temp at the t-stat housing with an IR temp probe).
2. The battery gauge shows much less than 14V (battery is at 14V when the truck is running).
3. I believe the gas gauge is working, based on how much it moves when I fill it up, and the low level warning light comes on when the needle moves to red.
4. Speedo doesn't work since the cable broke.
5. Oil Pressure gauge hardly moves. It starts out high when the truck is first started, then moves to a lower pressure after operation. However, the needle doesn't move very much while driving.

Do the RENIX gauges 'zero out' before they self-test? Also, are the needles supposed to move through the full range of their operational values? What affects the operation of these gauges? Can a bad ground do it?

Your 88 MJ in your signature?

Renix--do the grounds.

Commence standard Renix ground speech: replace the POS braided strap at the rear of the head to the firewall. Use a 4 or 2 ga cable, clean all surfaces down to bare metal, treat with an anti-corrosion agent, make the connections TIGHT. Adding a second unibody ground from the negative battery terminal to the passenger's fenderwell. Do the dipstick grounds--ICM, ECU, o2 sensor and more--bare metal, anti-corrosive, make the connections TIGHT.

There are grounds up under the dash, hopefully you won't have to go after them.

You can test the ohms for the various gauges at certain readings. If you still have issues when the grounds are done post back and I will put up the resistance values.

Note: your temperature gauge/idiot light sender in the rear of the head is a single-wire sender and needs to ground through its body to the head for correct readings. If you must use a thread sealant use one that is conductive.

Thanks Joe; yes, it's the 88 MJ in my sig.

I've worked on the grounds before when chasing down some blinker issues and high idle issues. All the engine bay grounds show less than .5ohms between it and the batt neg post. My temp gauge (it's a real gauge) is in an HO t-stat housing instead of in the engine block.

Just to make sure. the engine block sensor on the Renix is the CTS, not for the gauge. The gauge sensor would have been in the head, driver's side rear by the firewall. So, did I misunderstand you?

Sorry - I meant that the CTS is in the t-stat housing.

The sensor for the temp gauge in the cluster is still in the head, by the firewall.

Ok. Pull it, wire brush the body and reinstall it with a conductive thread sealer, see if that improves its reading.