Looking for the Short.

[VinsGN]

I’ve got an 87 GN with a draw/short on the battery with the ignition in the off position and key out. If I leave the battery connected and don’t drive the car for 6 or 7 days the battery is stone cold dead.

With a test light connected to the negative battery terminal the light comes on quite bright, indicating to me that the draw/short is pretty good and greater than what should be normal. To find basically were the draw was/is I started pulling one fuse at a time until the test light went out. Sure enough once I pulled the fuse for the security system the light went out, all other fuses made no difference. So….. I pull the fuse and said fixed.... wrong. With the fuse out it feels like the Power Master will not provide brake pressure, what gives? I don’t believe the short is coming from the PM as I do not get a brake warning light with the fuse in but, do when the fuse is out.

Is there away to disarm the security system with out pulling the fuse? Is the PM power provided by this circuit? I know this not the smartest thing to do security wise but, I just want to stop the short until I can fix it properly. Thanks.

 

[salvageV6]

What was the exact name on the circuit for the fuse you pulled out?

Was it on the fuse block or in a harness?

IF you pulled the 30 amp. power brake fuse out that would kill the pump and brake pedal feel.

And if the draw was on that fuse it could well be the fan delay relay is bad.

Its the largest relay on the drivers side fender with two connectors on it, remove them both to check the draw.

 

[VinsGN]

Salvage6,

The fuse I removed was the one from the fuse panel, not from the harness.

One of the other tests I performed was disconnecting the fan delay relay, no luck, the dead relay was not the cause.

Is there a harness fuse for the factory securty system? If so were is it located? Thanks.

 

[salvageV6]

The powermaster gets it's main power from the 30A brake fuse which is hot all the time via a fusible link (A) and does not go through the IGN switch.

The relay coil for the powermaster motor is triggered by the relays fuse power which IS controlled by the IGN switch so when you turn the key on the powermaster pumps up if the accumulator pressure switch calls for the motor/pump to run.

Having a key off draw on that fuse, assuming the fan delay relay is unplugged and not in the circuit, would lead to the powermaster relay or wiring being defective.

If the key were ON for this draw test it could be the motor trying to run which could be normal in that situation.

The relay should not be active with the key off hence no draw should be on that circuit with no fan delay relay in the picture.

The alarm fuses are taped to the harness behind the dash.

 

[VinsGN]

Thanks for the info. Using your information I'm going to dig a little deeper. I will post with what I find out (may take a couple of days) and get your opinion again, if you don't mind.

 

[salvageV6]

I should be here.

What area in CT you from?

I'm just outside New Haven, north.

 

[VinsGN]

I'm located in Enfield.

Have you ever made it up to Mark's Auto Cruise Night? I was hoping to shoot over there tonight but they have cancelled it d/t the pending rain. Really good even.

 

[salvageV6]

I've heard about Mark's cruise, but Mark H. from North Haven said they don't allow '87 Buicks in, so I never made it up there to try to enter it.

Never got a chance to just go up there to see it and all the cars.

I go to Hazzardville for the Barn auction on monday nights sometimes.

Nice area up there, I go to Windsor and Granby also for some collectible stuff and my buddy has a place in Winsted for his business.

We're all over the area with his furniture business.

The factory service manual from Helm Inc. or on CD also has great wiring diagrams and there may be some good ones on the vortex buick website or gnttype.org too.

 

[VinsGN]

Mark’s lets GN’s in and all sorts of other specialty cars (not just hot rods). My brother owns an 86 Lotus Esprit Turbo and him and I go at least 2 or 3 times a year. Always a cool ride home. :biggrin:

From what I've heard good weather Mondays have been bringing up-wards to 700 cars this season.

The car show on Main Street in Manchester hosted by Manchester Motor Cars is the show that will not let the GN in. They will not accept anything 80 or newer, that way the Fart Can Honda’s stay out.

Not this Monday (holiday) but the following Monday I'm hoping, weather permitting, to make it over to Mark's.