Park lamp/cluster/vaccum

[2genben]

I have a 1996 318 ram 1500 4x4 that has had me beating my head against the wall for about a month now. Running lights don't work nor do cluster lights as a result of the park lamp fuse blowing the instant it gets power. The nature of it would suggest to me that there is a short to ground somewhere that I cannot find. The failure occurred about a week after I pulled the bed to access the fuel pump so Naturally I thought I may have pinched a wire and so i went back and chased everything. I have a multimeter and a test light that I've been using. I have the factory service manual which I have been referencing. All grounds have tested good. I have not located any broken wires. I've tried isolating the problem between loads with no results indicating any of the loads would be a problem. All grounds have tested good. I've put hands on just about everything on the circuit and cannot find a short to ground. Interestingly I lost vaccum for 4x4 at about the same time. I couldn't get a new vaccum harness and I need 4x4 so I ended up just bypassing the vaccum system for 4x4. The reason I bring up the vaccum is I have only one suspicion remaining. I do alot of off roading and I thought perhaps that I likely drove over some sage brush or something that broke my vaccum line but I also know that there is a wire splice above the tcase which is tied into the parklamp circuit and perhaps the same brush that popped my vaccum line pinched the wires in the splice. It's kinda far fetched but that splice is the only thing I can think that I haven't touched, because I was unable to locate it. With as common as the HD switch problems are I'd think that someone might have some insight somewhere, however I have not been able to find any. If anyone has any ideas to help me isolate it I'd appreciate it. Otherwise how difficult would it be to wire the running lights and park lights into a different circuit on an independent fuse/relay?? I'm not an electrician though I have a decent working knowledge and experience doing both residential and automotive wiring. Thank you in advance. I appreciate your time.

 

[Nealuss]

As for the vacuum issue, the professional solution would be to smoke test it. YouTube will show you ways to make a DIY smoke machine good enough for occasional use. Basically block off one side of the line and blow smoke through the other end and the smoke will come out wherever its leaking. If you have the FSM you should have a vacuum diagram to use for this. As for the lights, I would start at the switch and check resistance going back through the park lamp circuit. Headlight switch is a common failure point.

 

[Marshall]

Poor ground should not pop a fuse.
These will be standard bulbs?
I would pull all of them, and hook up your test light to fuse, low side, than plug in one light at a time till the fuse goes, that is the shorted line, or socket .
You can also check each line with a quality meter , ohms, to see if you have a short, with power off