No Parks/Running lights

[sxcpotatoes]

Okay, I've been replacing parts and have run out of ideas.

Headlight switch is okay (I have three of them here, they can't all be bad).

Wiring pigtail was replaced with a new unit (wasn't singed or anything).

Still have the problem of the running lights/parks/dash illumination not working. Brake lights, turn signals, hazards, headlights, everything works except the damn parks & dash illumination. The fuses are all perfectly fine except it keeps blowing fuse # 8 so I have that one removed. (Hopefully fuse 8 is a seperate issue, I have hopefully narrowed that down to a short in the interior illumination somewhere, if I put a fuse in, and open the passenger door, as soon as the interior lights try to come on, *POP*)

Previous owner claimed they spent $250 having a shop check all the grounds/sockets in the back and front (but don't know if this happened). I pulled the tail markers and bulbs one at a time to see if it was a wonky socket or something. Don't have a multimeter, but will buy one if I have to to track down this problem and finally be able to drive it at night! I don't care about having interior lights at all as long as I can get the running lights working. Suggestions?

[1987cp]

Hm. Jumper +12V to various points on the circuit and see where it goes flaky?

If neither front nor rear running lights work, it can't be the extreme front or rear portions of the harness, has to be the bit that's shared .... I don't remember for sure whether the fronts go through that weird crescent-shaped connector behind the dash.


Test light FTW, in case you don't already have one.


If you're desperate, maybe run a completely separate running-light circuit to a separate switch?

[marquisman]

iv been through this before. there is a fueable link that powers the illumination. iv replaced it with a fue holder before. i think its the thiker yellow wire on the battery side of the solenoid. you can use a test like to find the burnt link or the owners manual might show it. iirc, i put in a 20-25AMP fuse to replace the fuse link

[sxcpotatoes]

Thank you very much mangs, I was toying with the idea of just running the seperate power to all the parks connected to a toggle switch if I had to. Will check this out tomorrow or the next day (gotta work tonight).

[sxcpotatoes]

Any pics or better description of precisely where the fusable link is at? I can't find it over by the battery/solenoid, I did find a thicker yellow wire, but nothing but wire into the plastic tubing.

[marquisman]

i dont have a pic, maybe someone else does? its a fuselink, among the lot of fuse links on the battery side of the solenoid. it will actually be part of the eye-terminal that goes on the solenoid post(black block of rubber, says fuselink on it). since i cant remember which one, its best to use a test light and probe the wires past the fuse links, for power.

[1987cp]

^^ But if that's wonky, and it supplies power to lighting in general, wouldn't it bugger-up the function of all lighting on the car?

[marquisman]

no. i have dealt with this issue on my buddies 88 merc. headlights work, brake lights work, signals/4-ways work. but, could not get the park/illumiation working. replaced the fueses and headlight switch. no change. test the wires comming from the solenoid, found a dead one. replaced it with a fuse holder and fuse and it fixed the issue. i will see if i can get a pic of what i did.

[sly]

here's a pic of my mess... it's in there somewhere connected to the lug on the solenoid closest to the battery.

[marquisman]

big mistake on my end. i apologize. the problem with my buddies 88 was no headlights, power locks and no clock/radio. would have to put high beams on to get locks to work. it was the thick brown wire comming from the solenoid(like in slys pic). but, its still quite possible the same sort of issue hides.

[sxcpotatoes]

Sigh, nothing but problems. I yanked a wiring harness from the kickplate on the driver's side all the way through the taillights from a '91 Crown Vic. Had a mechanic wire it in, he went back beyond where the wires were burnt up, and everything WAS working (somewhat). I had parks at least. The interior lights & opera light wiring headed up into the pillar was fried so I had the mechanic leave them unplugged.

Now, this morning I went out to make sure the dash lights work while it was dark enough to tell. And the front park lights are out, turnsignals work, etc, but the rear parks still work. One thing I noticed yesterday, the RDEF is stuck on whenever the car is running.

I can NOT turn off the rear defrost with the car running. I can put the key into the ON position and turn the RDEF on and off with the switch, but if it's running it's on. I pulled the switch last night, and ran it this morning... and EVEN with the switch out of the dash, the rear defrost is stuck ON all the time. There was frost on the back window above and below the lines, which if the sun melted it that early wouldn't have been the case.

I guess it goes back in the shop at the end of this week. May have to just have everything wired to toggle switches to cut on & off (parks, & rear defrost). The mechanic couldn't get the rear seatback out, he said he was at it with an air ratchet and couldn't get it at all.

I don't know if I should just give up on this one for now, pester 1980c10 to get that transmission out, put the purple-rimmed car on the road as my daily driver and rip the Blue car apart and try to rewire it completely.

[bigbeigeboat]

does it have an aftermarket stereo with an LED face in the car? the radio harness usually has a grey wire from the headlight switch for the instrument light dimmer and it wont drive some aftermarket units so it just gets cut. Its on a resistor so its not a dead short but if its flopping around it can cause all sorts of weird problems (and its connected to the park light circuit). also if they tapped ign hot power from the defroster (its physiclly close) and didn't diode the radio it can feed power back into the defroster.

without a meter and test light you'll never know whats going on.

[sxcpotatoes]

Thanks bigbeigeboat, I did put a Kenwood head unit in it, but it's had electrical problems ever since I got it. I will tell the mechanic about this, but I've pulled the radio/clock AND the 20A defroster fuses, and the defroster STILL is stuck on any time the car is running.

The previous owner supposedly replaced the entire fusebox (and at least one of the wiring harnesses have insulation completely burnt off the wires, which I had replaced). So I'm hoping it's just the way the fusebox is plumbed.

Once more, I just want this thing put together so it 1. can be driven at night & 2. doesn't burn to the ground with me in it. I can live without stereo, interior lights, power mirrors, but I would like not to get rearended or the car impounded for not having running park lights.

[sxcpotatoes]

AH-HA! I figured something out while on my way to drop the car back off at the mechanic.

The defrost switch is somehow getting power from the FUEL PUMP.

I can turn the key into the "on" position without starting it. As the fuel pump pressurizes/primes, the R.Def light comes on, the second it kicks off, the light goes off. I pulled the effing 20A defrost fuse and it STILL runs with the fuel pump. So I figured out the problem, now hopefully the mechanic can track down and fix the damned thing!

[bigbeigeboat]

well thats odd.

open the trunk and see if the former owner pigtailed the defroster grid off the fuel pump inertia switch.
those wires are IGN hot(when the fuel pump relay is closed) and right near the window on the drivers side.