electrical problem
 

started my 85 gslse today and noticed that i had no rpm , no oil tem ,cooling temp and gas needle wasnt working car started and ran like always speedo is working but everything else is dead what should i look for a friend of mine said the alternator is going but im not so sure thnks in advance

he is close but no cigar. be sure to check the pigtail connector behind the alternator.

here's a brief explanation:

the upper portion of the pigtail is your 12V which trigger's the alternator's F terminal on pre-89 alternators. in other words, when the key is in ON ignition, it sends signal to the alternator to start charging


the lower portion controls the gauges in your dash such as tach, water temp, voltage and gas along with dummy lights

the speedo works cause it's mechanical. tach gets signal from the coil. i'd also check fuses.

+1 on the alternator plug, had mine fall once and it did the same thing

Fuses, then alternator. Check the simple stuff first.

Because, if you monkey with the alternator and something else comes up, you haven't fixed the first problem (the fuses) and now have something else to confound the evidence.

i finally went thru all the fuses and found the onw that was bad thnks for your help