No gauge instruments or cooling fans

[Grover]

So, the other day after coming home from a charity event (everything was working well, car ran a little hot but did not overheat), I went back to the garage later in the day to take the car out. Everything was working. I pulled into a 7-11 and let the car idle. When I came back, the car was on the first red line. I then noticed that the cooling fans were not on (both otterstat and AC).

I swapped out Grady's fan box and installed the jumper thinking it was the box that failed. The fans didn't turn on. I then checked the fans connectors, they were clean. It was then when I started the car back up after letting it cool that I found the following.

The RPM tach does not work
The Voltage gauge does not work (confirmed the alternator is working with a volt meter)
The temperature gauge does not show the actual temperature (from a cold start it shows the second mark as the temp and then fluctuates)
The Oil pressure gauge does not work
The fuel gauge is pegged up.

I then remembered the thread in which Bill Robertson discovered that the dash, and cooling fan grounds, all run to the same point:
http://dmctalk.org/showthread.php?1371-DeLorean-Ground-Schematic/page2&highlight=delorean+ground

I checked the radiator bracket bolt and everything is on there and connected, and it had been cleaned about a year ago.

Any suggestions? The car will start up and run PERFECTLY fine, except for the above.

[Bitsyncmaster]

Check your fuse #5.

[Grover]

:p I didn't even think to check that. I assumed the fan relay box was the issue. I will check that tonight when I get home.

Once this issue is figured out, I need to find out why the fan module box I have is slowly melting. I will post a picture when I get home.

If all of my problems are linked to this one fuse while I was doing tons of other tests, I will have to remind my future self of KISS (Keep It Simple Stupid).

[Grover]

Check your fuse #5.

So I checked the fuses, they are all good. I also checked to make sure that the connectors are pushed in all the way, and they are as well.

I did note that when the key is in the 2 position, if I hit the headlight switch the electrical load causes the oil gauge to move slightly.

I am still at a loss of what to do next/start testing/look for.

[Bitsyncmaster]

That fuse 5 drives the volt gauge and the otterstat. So I would get a meter on it to follow where the break is.

[jmettee]

Agree, looking at the schematic, fuse 5 powers all of those things. Looks like a loss of voltage as opposed to loss of a ground. The other items run by the auxiliary relay sound like they are still working, so pull your fuse 5 & see if you have voltage at the fuse block & go from there.

[Grover]

Would the #17 Aux Breaker play a role in all of this as well?

When I get home I am going to do a light test, as well as test for continuity. Hopefully it is something easy to find/assess, but knowing these cars it won't be.

[David T]

Would the #17 Aux Breaker play a role in all of this as well?

When I get home I am going to do a light test, as well as test for continuity. Hopefully it is something easy to find/assess, but knowing these cars it won't be.

It is possible you have 2 separate problems. Fuse #5 for the dash and the circuit breaker for the radiator fans. Make sure you have the relay upgrade kit with the uprated circuit breakers for the radiator fans and the blower fan.
David Teitelbaum

[Grover]

It is possible you have 2 separate problems. Fuse #5 for the dash and the circuit breaker for the radiator fans. Make sure you have the relay upgrade kit with the uprated circuit breakers for the radiator fans and the blower fan.
David Teitelbaum

Thanks Dave. I have a spare set of the circuit breakers that I will try. I am pretty sure I did the update when I got the car 5 years ago, but I will double check.

[Grover]

So, upon further investigation it turns out that all of the instrumentation was not working because it was actually fuse #5 (I was counting horizontally, not vertically. AKA, I was checking and troubleshooting the wrong fuse, doh!).

But, the fans still weren't working. I have the PJ Grady Fan Fail Box. Turns out this thing just plain melted. I will post a picture later. This is the second box I have had this happen to, with this new box being a different revision. Has anyone else had this problem?

After I removed the box, I installed a standard relay and the three wire jumper. The fans work perfectly now.

So, any reason the box would over heat like this and fail? I have the Toby low-power fans in my car and it works perfectly without the box and just the jumper (never had a problem with anything melting).