1990 E-350 electrical problems - PLEASE HELP!!!

Our volunteer search & rescue team has a 1990 E-350 Box Ambulance. We're having an electrical woe. Everytime you push the brake pedeal, the passanger side brake lights are working just fine, but the driver side brake lights go completely out. The driver side running lights work, just the brake lights will not come on. Any help would be greatly apprecriated, as we need to fix this ourselves as we do not have the finanical status to go to a repair shop.

Hi, RE, Your E350 wiring problems, Let's start with the basics, Remove the tail lamp lense and check the bulbs, any black, discolored ones? Check the socketts, Green or corroded?, Correct bulbs?, Now very important, GROUNDS.Make sure the tail lamp assy is grounded to the body...Last but not least....Possible turn signal switch, as the brake lamp circuit is integrated thru the switch....Good Luck, Clay..

The bulbs are the correct size & aren't burned out. The sockets aren't corroded. As far as grounding is concerned, I haven't checked the grounds, but could it even be a ground wire causing the problem, since the running lights work? As far as the turn signal switch, I doubt that is the problem, because the turn signals work & being an ambulance, the turn signals are seperate compared to the brake lights. In case you're not sure what I'm talking about. Here is a link to an ambulance being sold on ebay, that has the same exact tail lights our's have: http://cgi.ebay.com/ebaymotors/1986-FORD-ECONOLINE-350-AMBULANCE_W0QQitemZ4618671241QQcategoryZ63735QQrdZ 1QQcmdZViewItem
Of course I could be wrong, and a ground wire could be the cause even though the running lights work, or if its still intergrated with the turn signals, than I guess it could be the turn signal switch.

No more replies no longer needed for the thread. Turned out it was just a ground wire problem. Took care of it.

Hi, RE, your no need to post, Just wanted to say,,,,,,,Glad you found the problem and solved it,,,,Isn't wiring a total joy!!!!!!!!! See Ya, Clay...

Clay, no wiring isn't a total joy, a total pain in my A** hole, especially with the ambulance. Believe me, ambulances have a lot more wires than any other vehicle out there, besides other emergency vehicles. This ambulance imparticular is a real pain because I'm trying to get it all fixed up & 90% of the problem is wiring problems. No one did anything to it since we bought the truck from a local hospital that went out of business back in the mid 90's. The hospital that owned it appearantly decided to tear it up for us before we got it. The tail lights had no ground wire on the driver side. The dome light had no ground wire. Half the warning lights were unhooked. One siren speaker unhooked. No license plate light. The truck has had mechanical problems like you wouldn't believe & has spent about 75% of its life with us out of service. I'm the one in charge of vehicles now so I'm trying everything I can to get the truck back in full service. Do yourself a favor, if you ever buy an old ambulance, make sure it was taken care of, if not your going to have a big pain in your rear to handle. Thanks for your post about what to check, apprecriated it much. Thanks, Tim.

Hi,Tim....Glad I could help in some small way, I am a retired ford tech, I did nothing but Auto trans OH/and diagnostics, But have spent many years doing a lot of electrical work on all kinds of vehicles, I'm still active part time for a school district working on on school busses, Hey, Talk about wiring problems, You name it they got it .....See Ya, Good Luck, Thanks for the reply, Clay...