97 chevy express left front and right rear dim bulbs

1997 chevy express.work van. my left front signal light and right rear brake lights are dimmer than the other bulbs, when i engage the turn signal left or right the signal will flash rapidly as if a bulb is blown but ive replaced all bulbs front to back, checked for corrosion and checked grounds under hood and in rear(the best i could anyway) no changes at all. i also have voltage and battery gauges that will jump from time to time while i drive, dont know if this is the same issue or not, im an autoglass guy so any help would be appreciated.

Those two are probably on the same fuse, so check that underhood. With the gauges 'jumping', that might be an issue with the alternator. Or battery.

Welcome to AF, does sound like ground problems, check the sockets, try grounding the sockets seperately, check for 12v at the bulb, also how are the parking lites?

I've changed my share of lamp sockets in Express and Savanna vans for high resistance and poor ground straps molded into the sockets. Just like the Econolines of the 70's and 80's. The guages is a different problem. Internal alternator brushes probably getting down to the nub and a very dirty rotor.

@82stang, gotcha on the fuses under the hood, thanks

@maxwedge i went out there tonight with a 12v tester and the sockets were all fine, the other lights work fine, forgot to mention in my post all my turn signals when engaged blink fast like a bulb is out, but ive replaced all bulbs front to back? thanks for your reply

@DeltaP so what do i do about the ground straps? any suggestions? should i get new pigtails? preciate your time

You can remove the lamp sockets from the lamp, remove the bulb and examine the contacts for burning,discoloration and loss of spring tension. Examine the plastic socket itself and look for melting,distortion,burning. You can check the resistance of the lamp by testing each contact to its wire end . Check the flasher terminals for dicoloration and for getting excessively hot when operating the signals. "Thump" the flasher to see if any changes in flash rate. Replace as needed.

Like mentioned above, if all lights flash fast, possibly the flasher is at fault. Should be under the dash somewhere.