The $500 Lesson: Chasing Down an Old Car’s Electrical Gremlin (Hunker Junker Restoration)

The $250 bandit!

Working on a car can be a lot of fun—as long as you don’t let the frustration get to you. Not even a week ago, the blower stopped working because the module burned out. Unfortunately, this was the second time that module failed, and each one costs about $250. The first failure wasn’t my fault; it simply burned out on its own.

Since the car is old, I assumed the component had just aged out. Old cars are notorious for electrical issues—rust, brittle wires, and parts that were never meant to last 40 years. I searched all over the country and finally found what’s called a blower module. They don’t make them anymore for this model, so I had to rely on an aftermarket company—apparently the only one still producing them.

Fixing cars is part fun
and part practical

I bought the part, installed it, and everything worked fine for a few months…until the weather turned cold. One day it failed again. That’s when I realized the component itself might not be the problem. Maybe there was a short, or a bad relay. Most sources said the relay was in the engine bay near the blower, but one mentioned it could be behind the glove box.

I took apart the glove box, and sure enough—there was a relay. I ordered a new one, hoping to save myself from buying another $250 module, since the relay itself was only $27. But when it arrived, it didn’t fit. I returned it, asked around, and everyone swore the car should have that relay.

What made it even stranger was that the second relay I tried almost fit—but not quite—so back it went. Meanwhile, the cold weather was settling in, and without a blower, the heat barely moved into the cabin. The blower was stuck on high, but only because something had burned out.

I checked with a good buddy of mine who’s been fixing up cars for years and does fantastic work. Compared to him, I’m an amateur. He looked it up and confirmed that the car should indeed have a relay. So I went back to the parts store to return the second relay. The guy behind the counter said the same thing—the car takes a relay.

But then we started talking about the strange chipboard module from 1985, and something I’d read online about the relay and blower resistor possibly being on the same board (not mentioned for this car or year.). He asked whether the car had climate control. And that was the key: this particular car came with optional climate control that didn't normally come with this car—advanced technology for its time—and the system combined components in a way modern parts don’t replace. They don’t make anything identical anymore. So after a wasted week and a half, I ordered my second $250 blower motor resistor/relay module.

Worried I’d just burn out another one, I checked the car thoroughly for shorts or loose wires. Finally, I looked at the fuse box and realized the prior owner had stuck a 25-amp fuse in there. The box isn’t labeled, so I wasn’t sure what size was supposed to be used. According to the manual, it should be a 20-amp fuse. Using a larger fuse would let the blower run too hot for too long, eventually frying the module.

The last thing I wanted was to spend a third $250, so I put a 15-amp fuse in instead. Some might disagree, since a lower fuse can limit max output, but this car already had a strong heater. Dropping to 15 amps made sense to me—it ensures the cheap fuse blows before the expensive module does.

So far, so good. The new blower module works, and that’s important in the Upper Peninsula, where winters are brutally cold. Yes, I lost about $500 and a week and a half of time, but if I had taken it to a mechanic—paying for diagnostics and repairs—I suspect the bill would have been $800 or $900. Mechanics have overhead to pay. Fixing it at home doesn’t cost me anything but time and a bit of frustration.

I put the old module on the shelf. Maybe one day I’ll find the little burnt-out component, solder in a new one, and have a backup. You’re either a car person or you’re not, and I genuinely enjoy tinkering with old cars when I get the time. This one should be finished in a few months, and I’m already looking around for either a 1950s Santa-style truck or a cool old Land Rover to fix up—something I can put a winch on and take hunting, fishing, and winter driving. Meanwhile, I’ll keep enjoying the luxury of this Riviera for nights out in downtown Escanaba.