Electrical Issues

[RCassedy]

My blower fan was making loud noises when running A/C. I took the fan out to inspect. I found that the plastic cage was warped and damaged. Reinstalled it until I could get a new cage. Started the car and the fan didn’t work. I had forgotten to reattach the black wire that attached to one of the bolts that holds the fan in. While it was still running I attached the wire. A little sparking happened and the fan was spinning. I shut car off and quit for the day. I went to drive it the next day and noticed that the power door locks and power windows quit working. The fan also will not blow on high anymore. I also noticed that the inside dome lights quit working. I checked the fuses and one was blown. It was the Gauges/Trans. Replaced it and have since checked all the fuses for continuity and they all check out. None of the items listed above still work. It seems like a ground problem but I don’t know where to look anymore. I’m desperate for help.

[TJ Hopland]

Wish I had a 70 manual to look at this puzzle.   Got to be something in common with those symptoms but I don't know what that would be.   I was going to say fusible link but there is one that runs stuff on all the time and one that feeds the key for the rest and you seem to have things on both sides not working.

[klinebau]

The higher blower speeds are activated through the blower relay and the power to the blower in these modes does not flow through the fuse box.  The power comes through a fusible link instead.  I am sure that you blew the fusible link and that is why your high-speed blower is not working.  I assume the other systems not working are also connected to this same fusible link.  The fusible link should be one of the wires connected to the starter.

I am surprised that connecting the black wire caused this but I supposed it must have created a current spike.  The black wire should be the ground for the blower.  The tan wire with the harness connector is the power for the blower.

[RCassedy]

Thanks. Can anyone tell me in more detail how and where to exactly find the fused link. I know it’s a bulged area of a wire.

[Cadman-iac]

Thanks. Can anyone tell me in more detail how and where to exactly find the fused link. I know it’s a bulged area of a wire.

Hi Russ,
  I don't know if this will help much,  but here's a few pictures of the schematics for a 70 Cadillac Coupe Deville.
The first two are from a Motors service manual, and the rest are out of the 70 Cadillac service manual.
  The main fuse link that you are looking for is located at the starter. There's 3 coming off of the terminal with the battery cable attached.
Usually a blown fuse link will be more flexible because the wire has burned up inside the insulation. The insulation itself is probably still intact, as it's supposed to be able to protect the other wiring around it.
Hope this helps.

Rick

[RCassedy]

Thanks everyone for your replies and knowledge. I jacked it up this morning and one of those fusible links was blown. Fixed that and the door locks and power windows work again. There is one more wire I have a question about. It is a red wire connected to the starter solenoid and it runs up with the large positive battery cable. Half way up in the engine bay the wire is missing and signs of burnt insulation. No other signs of the wire. I will take a photo and post it soon. Thanks again for your willingness to help.

[Cadman-iac]

Russ,

That red wire, which terminal is it attached to on the solenoid? That would help to identify what it is supposed to be.
Since you said it was parallel with the battery cable,  I'm just guessing that it is connected to the same terminal as well.  My guess is that it is supposed to go to the alternator, but I am only guessing at this point.
Someone may have had a problem with it and rerouted it to the battery directly, leaving that part of the old wire there.
Let us know what you find.

Rick

[TJ Hopland]

At the starter you should have the fat battery cable then 5 smaller wires.   3 of the smaller ones are the fusible link wires.   One of the remaining ones goes to the S terminal on the solenoid which engages the starter.   The last one is on the I terminal which goes to the ignition coil.   

The I terminal comes live when the starter is engaged.   Its a 2nd feed wire to the coil in addition to the one with the resistor wire.  The idea is its a more direct path that bypasses the resistor to give you a little boost during cranking since the starter is sucking most of the power. 

[RCassedy]

Photos

[RCassedy]

It is connected to the same terminal that the battery cable is. I will check my coil to see and follow the wire connected there. What is the purpose of the resistor thing connected at the coil? When I replaced the coil that thing broke and I didn’t replace it.

[35-709]

Resistor thing at the coil? 
Is the picture below similar to what you are referring to?  If so, that is an ignition interference capacitor for your radio.  If you don't listen to the AM side of your radio, it doesn't make much difference if it is not there, it removes/blocks the ignition noise from your radio on the AM band.  Ignition noise doesn't affect the FM side much.