C4 89 Vette, temp not showing on dash

Rocky · 01-17-2009, 04:28 PM

Temp not showing on dash, so I replaced the sending unit, and digi dash still stays on LO temp. Is there a fuse for the sending unit to dash? Any ideas?

Thanks,

Rocky

shakedown067 · 01-19-2009, 08:34 AM

Have you checked all the fuses? I'd think there'd be one for a sending unit. If not, you must have a frayed wire. Good luck.

gmjunkie · 01-19-2009, 10:26 AM

Did you change the right sending unit?? There is 1 in the right head between 6 and 8,and 1 under the throttle body!! Which is not working the analog gauge or the digital read out??

Rocky · 01-19-2009, 10:43 AM

The sending unit located by the throttle body is for the fans. I replaced the sending unit located in the head next to the heater box.

I was at a loss as to what to check next.

I took the car over to a guy who takes care of wiring issues for a GM dealership. The new sending unit is OK. I need to check the following:

Sending unit wire, from the sending unit to the joint connection.

If wire is ok, then check the wire from the joint connection to the dash read out.
If ok, then Digi Dash is the problem.

shakedown067 · 01-19-2009, 12:37 PM

I can't say i've heard of the Digi Dash going out quite like that. The bulbs usually just burn out. I'd certainly say you have a wiring issue. I've got a great guy that deals with electrical issues in Pinellas Park if you need someone to take it to...he fixed the A/C-Heater wiring issue with my car. :thumbs:

gmjunkie · 01-20-2009, 06:59 AM

Quote:

Originally Posted by Rocky

The sending unit located by the throttle body is for the fans. I replaced the sending unit located in the head next to the heater box.

I was at a loss as to what to check next.

No,The sensor under the throttle body controls the Digital Dash and other functions of the ECM for Closed loop operation!! The one in the head controls the Cooling Fans Operation and Analog Gauge through the ECM!!

Rocky · 01-30-2009, 05:06 PM

I have replaced both temperature switches, the one behind the oil dip stick, and the one located on the Throttle body. We have put a meter on the plug, and it reads 4.9v, which I was told was the correct reading for anything going to the digi dash. Today I sent the cluster to the person who sold it to me, for testing.

If it tests OK, then I am back to square one.

shakedown067, sorry I didn't remember your guy in Pinellas Park. I would have tried him before sending the cluster off.

Rocky

Rocky · 02-06-2009, 08:30 PM

The temp gauge on the dash cluster, is fed from the sending unit located just in back of the oil dip stick. I followed the green wire and it goes into the same harness along with the wiring to the starter. The wire was broken in half. I spliced the wire, and now the gauge is working.

Hopefully, this thread will help someone in the future.

Rocky