AkiraHunter

Hey guys, I have this ridiculous issue in the fan circuit. Lemme start and say the car is a 95 Z28, engine mods on request, so you know which relay system I use. My issue first started not long ago while i was on the parkway (non jersey guys, its a highway, with tolls lol) my fans cut out and the car got hot. Once I got to where I needed to be, long story short, I pulled the assembly, and slapped a universal fan in, wired a switch to a relay and used it to get home the following day.

Now the fun part: I wanted to keep the use of my original shroud, so I bought two new motors, and 3 new relays and replaced them. Everything seems good. Except now, the fan fuse keeps blowing. Using Mitchell and Shoebox's diagrams I traced the wiring from the fuse box, to the fusible link. Everything was good, no breaks, nothing. I cleaned the connections on the junction box, the grounds, and connectors at the fans. Also, worth noting I have an SLP manual switch, which, has no change if its installed or not.

Here's the confusing part: the fan fuse will ONLY blow if I shift into drive. If I let it idle in park, it'll cool the planet off, second I shift into gear, pop. So I'm stumped. I've also checked the O2 sensor connections since I know it gets power from the same fuse, no breaks or issues there, I have no EGR, so thats not it, and unplugged the EVAP and still no change. Also thought I may have a pinched wire near the shifter, so, pulled the console, nothin there. The car has a TH350 in it, so it has no electronics, and the old harness has been capped for years.

So I'm stumped. Sorry for the book, but I'm literally at my wits end.

Guest47904

I assume you have the factory fan configuration back in.

If shifting the tranny to drive shorts the fuse to ground, either it is mechanically moving a wire, or electrically doing it.
Have you looked at the shift linkage from under the vehicle?

My suggestion is to pull the fan fuse and find the contact that does not have 12 volts on it when the key is on. Now put an ohm meter lead on that contact and the other to ground. Now shift the tranny into drive and see if the connection goes to ground. Try it with power off and power on.

Now start wiggling wires until the short to ground is no longer there.

AkiraHunter

Yea, my stock shroud is back in. I'll try your suggestion when I get home from work today. I didnt check the linkage under the car, I only went as far as the fan harness up front tracing it. However, minus the dmm part, I did do the wiggle test, but I'll try again.

Shes worse then a gf, I promise her more upgrades and all she does is want more money outta me

ps: on a side note, speedy, nice truck. I have a 92 k1500. I got a 6.0 currently being assembled thats gonna be in front of a 4l80e. Gonna be fun

EDIT:
wasn't able to check today, by the time I got home from work it started raining, not having a usable garage, I wasn't able to check anything. Hopefully tomorrow its clear after work.

Guest47904

Have you tried just pushing the brake pedal and not shifting into drive and see what the fuse does? I ask this cause there is a shift solenoid.

AkiraHunter

I have, it wont blow the fuse until I shift. Although, I don't think I do have a shift solenoid, since the trans is a TH350 now, unless theres another one I'm not aware of.

Sparkz28ss

I know on the m6 cars the rev. lock out solenoid and the skip shift noid are on the same circuit with the fans...

AkiraHunter

Yea, but the A4 cars don't come with them though right? Plus, I have a TH350 in it now.

bw_hunter

There is a park lock solenoid located next to the shifter on A4 cars. If you have to push the brake pedal to shift from park it's still there.

You can physically remove it and leave the connector unpluged without any problem.

Just remember that it's disconnected when kids are in the car...it can be shifted out of park at any time....

AkiraHunter

Hm, is that the box that has the yellow plugs and SRS stickers on it? Since I've owned the car in 07 its always shifted outta park without the brake pedal depressed. Which works perfect for my pistol grip shifter TH350. However, I did unplug it the other day as the console is still off, and it made no change in the issue.

btw, I dont have kids, and usually dont have them in my car, but I understand and appreciate the concern.

bw_hunter

The solenoid I'm talking about sits right next to the shifter on the passenger side under the console. It is cylindrical and has snap lock conectors at both ends. I believe it's on the same fuse circuit as the 6-speed cars solenoids. Is it possible that the thing is disconnected but the wires are pinched under there so that when you shift the hot wire grounds out?

AkiraHunter

Huh, ok, I dont recall seeing it, but I'll look again when I get home from work. Don't even remember seeing any other plugs. No harm, I'll check.

AkiraHunter

Ok, so I checked, and that other solenoid is there. I got home from work very late, and all I had time to check was for that, plus I couldn't find my DMM. That solenoid was plugged in, I unplugged it, no difference, still pops fuse when put into gear. Also traced back the wire as far as I could, nothing pinched or broken. Hopefully get home earlier tonight, find my DMM, and also get under the car.

bw_hunter

OK, look at the reverse lamp switch..that's the only other electrical device that could be affected by moving the shifter from Park...

AkiraHunter

Ok, I believe it's solved lol. Worked on it all weekend, checked the reverse lamp switch wasn't that. Got ahold of my DMM, and a power probe, and started tracing down. Long story short, everything from the body connector over to the relays and fuse was good. Then tested the connector on the pcm side, and I showed a short. Fearing it was my PCM, I disconnected it and rechecked, it was still there. Changed my pants, and kept looking. It's somewhere in the body harness that goes into the dash. I checked as much as I could, but couldn't find it. So I just rewired and soldered a new wire from the pcm side connector to the other connector. Runs again, no more popped fuses.

On a side note, it seems the car runs better early in the morning. I drove it to work this morning and usually first thing in the morning it has a small miss. Thinking back on it, since I now know that O2 heater is on the same circuit, it's probably been starting to short out for some time now, because after a few mins of driving it'd clear up. Probably just getting warm fast, the car does have 12.5:1 compression... lol.

Anyway, thanks for all help, you guys are great.