When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
My son and i are refurbishing a 1978 f250 4wd standard cab. We have rebuilt the engine and brakes and are have an electrical issue. When you turn on the running lights both blinker indicator light up on the dash light up and the blinkers do not work. We are also not getting power to the passenger side rear brake light. I'm was suspecting a grounding problem but have been unable to correct with a ground wire from the battery and grounding out probably spots.
My 79 did this awhile back when I first got it and I believe the way I fixed it was by putting all new bulb connecters front and back but it's been awhile and I could be wrong so I'd wait for others opinions first.
Sounds like you have two problems.... likely bad grounds and no juice to the brake lights. Check the grounds at all the running lights (even at the front).Make sure your brake light switch is functioning with a test light and then you just need to trace the wires.
my 78 did this also. for me it was only the left turn signal. pulled the front left bulb and cleaned the inside of the connector, it has been good ever since.
Do the simple things first replace and clean dual element bulbs, truck sat idel in a pasture for years so that is what we will do first and check all grounds