NE1 ever upgrading wiring using a relay to the blower motor?

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shanker

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I'm just wondering if this is possible...I'm getting the A/C working in my wifes duster and when coming to a stop at a red light, or at idle...the blower motor comes to an almost stop as well I can see a big pull on the ammeter.

I've already re-done the headlight harness, but that doesnt solve my daytime driving issues when the voltage drops.

Is it possible to wire in a similar relay for the blower motor and run a dedicated large gauge wire to the motor itself?

I'm just trying to figure out how to do it and maintain a Low/Med/High speed setting.
 
You should not need to. You need to measure the voltage and draw of the motor. Check the fuse for amperage, and feel around the switch, fuse, etc, for HOT spots, as well as the motor itself

Either you have a bad connection starting with the fuse, the switch, or the motor itself is bad.
 
your alternator may not be big enough to handle the draw anymore. have you added any circuits such as electric fans?
 
66plyValiant said:
your alternator may not be big enough to handle the draw anymore. have you added any circuits such as electric fans?
Click to expand...

That could be part of it. Have you monitored battery voltage under the "low speed" conditions?

How's the bulkhead connector?
 
66plyValiant said:
your alternator may not be big enough to handle the draw anymore. have you added any circuits such as electric fans?
Click to expand...


the only electrical upgrade has been a CD player in the glove box, but no other sound system mods and the headlight harness was the only other "mod".


I've had problems with this alternator since I got it (Autozone)...I let the duster stretch out her legs and ran it up to 110 and after that the alternator was making noise...so I warrantied it out and have been having bad luck since then.

The voltage drop going to idle is immense..bad enough that the radio would turn off at night time if the headlights were on.
 
Before condemming the alternator, you need to make some tests. You along with many others, may be fighting deteriorating bulkhead connector problems, along with other connectors and wiring.

READ the Mad article which, down the page, shows an important, simplified diagram of the layout of these systems

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

which came from here:

http://www.madelectrical.com/electrical-tech.shtml

ON the diagram, follow the charging lead and battery feed as it comes from the battery, through the fuse link, in the BULKHEAD CONNECTOR , goes through the AMMETER, and encounters the IN HARNESS SPLICE, and goes back out the BULKHEAD CONNECTOR to the alternator

These are all important points that can fail. Even the "welded" "in harness splice" has failed. This is a splice, taped up inside the under-dash harness, that feeds the headlight switch, the "hot buss" in the fuse box, and the ignition switch, and a couple of other things. It is NOT fused, and they HAVE failed.

Get out your meter, or buy one if you don't have one.


FIRST, check for voltage drop in the ignition harness. Turn the key to run, engine off. IF you have points, they much be closed. Put your meter on the coil neg, and if the voltage is "close to battery," the points are OPEN. Bump the engine until this voltage is LOW

Next, put one probe on the battery positive post, the other on the IGN feed coming out of the bulkhead, going to the regulator "I" terminal or the "key" side of the ballast. Normally "dark blue."

You are measuring voltage drop across the harness and are hoping for a very low value. Anything over .2V is too much, over .3V means get serious and find the problem.

Your top suspects are the bulkhead connector, the IGN switch connector and the switch

NEXT start the car, all accessories off, and running at a good fast idle. Let the battery charge to "normal" (ammeter centered.) Measure battery voltage, it should be more than 13.5, less than 15. Optimum is around 14V AFTER the engine and regulator have warmed up!!

Now, turn on some loads the headlights, the blower. Prior to this, you need to have located some major points in the car wiring. You should clip a lead to each side of the ammeter and bring them out under the dash where you can access them. You'll have to unhook the battery ground for safety.

Identify the blower fuse for sure.

Now with the car running, loads on, measure some points and write them down, post back here:

Battery voltage across the posts

Alternator output stud to block.

Both fuse clips to ground for the blower motor.

Both ammeter terminals to ground from your clip leads on the ammeter

IN ANY CASE I would pull the bulkhead connector apart and inspect it for damage, corrosion, loose/ overheated connectors.
 
Ditto 67Dart273, can't be your alternator since it should run for an hour off the battery alone. The alternator serves only to recharge the battery.

You would need 3 relays to bypass the switch for low, med, & high. That wouldn't help if a drop to the dash still exists. In all my 60's cars I use a relay for the blower high position only. That keeps the valuable L-M-H and electro-pneumatic switch (factory AC) from melting. You probably don't need that for L & M positions since they switch in a series resistor (in your air box). Don't keep using it if your blower is slowing way down, until you fix it. Motors draw very high currents when they stall.
 
Also, don't forget the pully size. On street driven daily drivers i have fixed this "at idle" problem by switching to the smallest pulley available. I look in junk yards for 80's custom vans, they have real small pully.
 
BillGrissom said:
In all my 60's cars I use a relay for the blower high position only. That keeps the valuable L-M-H and electro-pneumatic switch (factory AC) from melting.
Click to expand...

I was hoping someone else was doing this and had a diagram of the switch and relay terminals handy. I had to put a relay on my A/C clutch when I switched over to a Denso compressor too.
 
all these relays aren't nessasary, it helps on headlights but if you have good wiring which most 60's cars don't you won't have a problem

save your money and check the wiring, if its bad replace it all not just some of it
 
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