Gauges not working...
I have this posted in the electronics forum but Im not getting much feedback. Ive got a 98 TA but the engine harness, gauge cluster and computer are 99-02. My gauge lights come on as well as the indicators etc but I have no readings on any of the actual gauges, oil pressure, water temp, volts or even RPMs. I thought it might be that the gauges were the 98 so I switched those to a set from 99-02 but still nothing. I really need to get this issue resolved, any ideas?
P.S. Ive checked the gauges fuse and its fine, what else could it be? The only wiring that has been messed with, to my knowledge, are the ones down by the shifter. I installed a Hurst QS. I wouldnt think anything down there would effect my gauges but who knows. Any help would be greatly appeciated, thanks!
Last edited by B(o)(o)sted98TA; Nov 18, 2013 at 04:45 PM.
I got my oil pressure and volts gauges to work, however, I still don't have a reading on my water temp or my RPMs...
Can someone please help me out here. I know someone has the answer
P.S. Ive checked the gauges fuse and its fine, what else could it be? The only wiring that has been messed with, to my knowledge, are the ones down by the shifter. I installed a Hurst QS. I wouldnt think anything down there would effect my gauges but who knows. Any help would be greatly appeciated, thanks!
the 99-02 pcm puts out a digital serial data signal that covers all the gauges except for the oil pressure....the 98 gauge cluster uses anolog signals for each gauge individually....you choice of getting a 99-02 gauge cluster is what you have to do to get it all to work....
knowing that...
the Digital Serial Data comes from Pin #58 of the Blue connector
the oil pressure signal on all 98-02 fbodys was wired directly to the oil pressure sensor, and it s a single wire sensor that uses a pull down voltage to read the pressure.
on the 99-02 pcm there is a tach output for an aftermarket tach out on pin #10 white wire on the RED connector if I recall correctly..
also, this may help for anything else you may need.....
its very possible you have all the right stuff going to the dash, but no signals coming into the pcm to send to the dash.....meaning, possibly no coolant temperature because the ECT sensor is not pinned correctly, or no speedo because of no VSS signal...
http://www.ls2.com/boggs/torques/99pinpcm.htm
Speedo doesnt work due to the th400, ill have to splice into the wheel speed sensor for that I think.
Where should the white wire for the tach be going? Doesnt it run down to the connectors behind the kick panel? Do you know which one goes to the dash on the 98 Body Harness?
And what do you mean about the ECT sensor?
http://lt1swap.com/98-02_ls1.htm
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Any other input??? I'm stumped.
Also on the C105 connector on the shock tower (the WHT wire (tach signal) that goes into pin G) is there supposed to be another wire coming out the other side (the side closest to front of car?)
Last edited by B(o)(o)sted98TA; Oct 10, 2013 at 08:33 PM.
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Speedo doesnt work due to the th400, ill have to splice into the wheel speed sensor for that I think.
Where should the white wire for the tach be going? Doesnt it run down to the connectors behind the kick panel? Do you know which one goes to the dash on the 98 Body Harness?
And what do you mean about the ECT sensor?
so what I mean by the ECT sensor, is that you need to verify thru the PCM and a scan tool that ECT is indeeed working....
the ECT Gauge not working could be as simple as the PCM not seeing any data from the ECT sensor...which could be a bad sensor, or it could be just a simple problem of the pins from the sensor in the wrong holes in the pcm
the Tach is normally sent down the Serial Data line to the gauge cluster...
if you dont have it straight from the pcm data signal, then you either dont have the correct wire going to the gauge cluster, or you dont have a working cluster, or you dont have a crank signal going to the pcm...
if the vehicle starts, then you have a crank signal, and we can eliminate the sensor as the problem
the White wire # 10 will not drive the factory gauge cluster...it is for an aftermarket tach such as one you might buy from Autometer...
it is also a 4 cylinder style signal(why GM chose this instead of an 8 cylinder signal...I have no idea)
Correct on the Wheel speed sensor... you will need to splice into on of the rear wheel sensors, and then change settings in the pcm to reflect the new pulse per rotation and pulse per mile settings.
Now I just need to do my ECT. The sensor is brand new so I doubt thats the issue. Question is, do I have the right one? It has 2 wires coming out of it, am I supposed to have 3?
Now I just need to do my ECT. The sensor is brand new so I doubt thats the issue. Question is, do I have the right one? It has 2 wires coming out of it, am I supposed to have 3?
Blue Connector pin 74 for signal, pin 80 for ground
They do not have the same calibration or even the same type of signal...
2 wire is resistance in ohms...
3 wire is based on output voltage.





