1979 CDV Fuse Block Removal/Service?

[0maha]

Need some help here.

The short version of the question is how do I remove the fuse block on my 1979 CDV so as to gain access to the wiring on the back?

This started because my climate control blower fuse burned out, and took the socket on the fuse block with it.

Some background on this earlier thread: http://forums.cadillaclasalleclub.org/index.php?topic=159211

I found this YouTube video and it seems like the exact situation: https://youtu.be/qS9d2lH916k

But I'm stuck trying to free up the fuse block in order to install the aux fuse holder.

I found two long bolts that I would have thought held the block in place. Got them removed (and that was no fun at all), but the block is still hung up.

This pic shows the location of the bolts I removed.

Access to the area is horrible, and I'm trying not to break stuff. The 40 year old plastic connectors make me nervous.

Any advice?

[TJ Hopland]

Is a 79 one where part of the fuse block is also the bulkhead firewall connector?   If so I think you first have to remove the connector and harness under the hood.

[0maha]

I was wondering about that.

There's this thing on the firewall that looks to be in about the same position. It's next to the power brake system.

As for getting it off, any ideas how it's attached?

[0maha]

I should add this: With the two bolts removed, the fuse block is very loose. Those bolts are pretty long...like 2.5" or so. I think they screw all the way into the firewall or something behind it.

There is a plastic piece directly on the cabin side of the firewall that acts as something of a standoff for the fuse block. Holds it away from the firewall.

[TJ Hopland]

The bulkhead connector should have at least one bolt in it from the engine side.  If its just got one it will usually be in the middle.   IIRC you loosen the bolt then wiggle the connector till it hits the bolt again then loosen more then wiggle more till its out. 

[The Tassie Devil(le)]

TJ is correct on this.

The central bolt is a captive bolt, and as you unwind it, it will draw out the plug with it.

Bruce.

[0maha]

Much appreciation, gentlemen. Found the bolt, and it came right out just as described. The fuse panel is now free.

Only bad news is that connection is a hot mess. This car was undercoated, and those blades are full of it. Going to be a chore to clean up.

[TJ Hopland]

I don't think its undercoat, every one I have been into looks like that.  I think it is or was some sort of dielectric sealing grease.   I don't know that it hurts anything but it does make it difficult to inspect things. 

Packard 56 is the clue you need to find replacement pins for those.   Last one I had to work on I was able to find them in stock at my local NAPA. 

[0maha]

I think you're right. Just got finished cleaning them up and whatever that gunk was, it came off too easy to have been undercoat. I'm going to go ahead and slather it with fresh dielectric grease anyway...can't hurt, might help as they say.

I'm about to start putting it back together. Hopefully all those pins line up! They don't look damaged, so I think I'm ok there.

Mostly I'm just hoping all this solves the blower no op problem.

[0maha]

Thanks again, gentlemen, for your help! Thanks to your guidance, the job is done. And I'm pleased to report a positive result. Just got back from a 50 mile drive and the fan is working perfectly.

I'm still a little curious about the root cause here. I'm concerned that the fan is pulling too hard on the system. I'll probably pull it out and give it a once over pretty soon.

The AC itself is weak. It blows cold, but not like it should. That's on the list. But there are some other items on the list ahead of it, so it will wait.

Thanks again.

[TJ Hopland]

I assume the 79 had a relay panel above the fuse box like the 78's did.   Every 78 I ever saw (I wasn't shopping for show cars) had the relay for the blower pretty melted most to the point of no longer working.   I saw various attempts at getting the blower working again, most not very successful.   

I believe initially its the relay itself that heats up and starts to distort which then causes a cascade effect leading to the whole socket and terminals melting.   If you can find a good replacement thats obviously an option.   If you want it to look stock you can get a replacement relay then hog out the damaged area of the socket and replace with standard terminals.  You then feed the standard terminals through the modified socket and hook them to the relay then feed them back in so the relay is held in by the remaining still good terminals.    Option 2 is get a universal 30a 'Bosch' style relay.  Release the not damaged terminals from the block and install those on the new relay and replaced the damaged ones.

As to why they failed?  Dunno.   I suspect it was a marginal design for the relay.   Perhaps debris starts to clog the evaporator coil and restricts the airflow which puts more strain on the blower?   Bearings get dry and start to drag a bit?   Replacements often seem to draw more current and move less air especially now days.     

[0maha]

Funny you should mention the relay. When I first started on this some weeks back, that's where I started. One of the contacts for the relay had burned through the panel. Got that cleaned up just like you described, by pulling the wire through the panel and pre attaching it to the relay.

FWIW, on my 79, the relay panel is attached to the Left side of the fuse panel with a metal clip.

My guess at the moment is that the AC needs charged. As is, it doesn't produce enough cold air, and the system can't keep up. The result is the fan running continuously at 100% power.

I'm going to go to my AC guy next week and see what he says. I don't know anything about that stuff. Maybe it can just be charged? Maybe some components are shot? Maybe it needs upgrading to new refrigerant? Have to see what he says.

[TJ Hopland]

Pull the blower out for a closer look at things.   See how much crap is in there and clean it if it needs it.   Also inspect the blower for how easy it turns and if it looks vintage or kinda cheap like its a more recent replacement.

[bcroe]

Without a doubt, the earlier car wiring was practically intended
to fail in the long haul.  None of the contacts have noble metal
plating, so anything high powered is going to combine heat and
moisture to start corroding.  Once that starts, the process soon
snowballs and burns out.  Blower motors, rear defoggers, ....

Which is part of why my cars have a lot of custom wiring.  More
reliable and serviceable.  And something to keep moisture away
from plug in contacts helps.  Headlights, ...   

Here I usually manage to wire in a waterproof fuse holder in
place of a burnout, by connecting to external wires and leaving
the original blank.  Bruce Roe

[0maha]

My guy has some R12 on hand, so we're going to try topping it off and see what's what from there.

Got a question on the blower: Suppose when I pull it I find that it's shot. What then? There have been some comments here that replacement units currently available are sub-standard. Are there any specific recommendations on which one to buy if it comes to that?

[35-709]

Best option, IMO, is to have your original motor rebuilt.

[TJ Hopland]

That is assuming he even has the original now......

I would pull it no matter what.   That will let you feel how stiff or free it is as well as clean things.   The evaporator (cold radiator) is the first thing in the air path so it will catch anything that the blower has sucked up in the last 31 years.   IF that is all full of leaves and crud its not going to matter what kind of charge it has or how good the wiring is. 

You may also get it out and see the made in china sticker or that the fan blade is 1/2 the size of the housing.

[0maha]

Good thought on the leaves and such. I'll pull that motor tonight and have a look.

[0maha]

Thought I'd update...

The blower motor checked out. Looks fine, tests fine, no debris, etc.

Never did get around to having the R12 topped off.

The repair held for about a month. Given how little I drive this car, that's probably two days in the real world.

Back to square one. My new outboard fuse holder looks fine. Fuse did not blow.

When it went out, it was like there was a self-resetting breaker in the system. It was blowing, cut out for a half a beat, came back on. I was almost to my destination (like a block away), and it blew the rest of the way there. Arrived, turned off the car. Blower hasn't worked since.

I don't understand that at all. Any thoughts? In particular, I'm wondering if my root problem isn't down inside the controller/programmer stuff.

[bcroe]

On my 79 Eldo all level blower currents flow through the controller,
perhaps your 79 is the same.  Others have had the controller burn
out from high blower current.  The non CC cars use a relay to feed
high blower current directly from the battery, and I modified my 79
to do the same, yes an additional relay.  The article is in the July
1999 SELF-STARTER.

Another owner had the contacts burn out on his 79 Eldo CC
controller, can not find the picture right now.  Bruce Roe