Need help with fresh air fan relay, Pin 86 is hot when car is off Options

[gord]

I'm trying to diagnose some electrical gremlins in my car. This is complicated by the fact that a previous owner somehow wired the fuse panel incorrectly, so I've been tracing wires trying to sort things out. I've been making progress, and have at least got things to a point where I don't blow a fuse as soon as the wipers or fresh air fan are turned on — but the problem now is that I can run the fan and wipers with the car turned off.

I am presuming that this is not normal, but please correct me if I'm wrong.

Car is a 1972. From the wiring diagram, I can see that pin 86 on the fresh air fan relay should be powered from the "X" position of the "steering column switch" (the ignition switch?), via the 15 post in the headlight switch (which I believe means it should only be powered when the ignition is turned on)... so I'm guessing this means removing and rewiring the ignition switch?

Looking for any tips or advice, or if anyone has suggestions about what else I should be looking at.

[gord]

A follow-up to this, in case it will help anyone else:

I spent a couple of hours going though the fuse panel and relays with a continuity tester, and was able to put things back in order. Here are the notes I made to sort out the relay connections with respect to the fuse panel:

51: Horn relay
- Pin 30: from S11 Hot (red)
- Pin 85: to steering column pin S- (brown/white)
- Pin 86: from S8 Hot (red/white)
- Pin 87: to horn (black/yellow)
- Pin 87a: nil

54: Fresh air fan relay (load reduction relay)
- Pin 30: from S12 Hot (red)
- Pin 85: to ground (brown)
- Pin 86: from X (headlight switch and ignition) (red/white)
- Pin 87: to S8 Hot (black/red)
- Pin 87a: nil

53: Fog light relay
- Pin 30: from S10 Fused
- Pin 85: to S1 Hot
- Pin 86: to fog light switch pin K
- Pin 87: to fog lights pin 56a
- Pin 87a: nil

66: Buzzer
- Pin 86: from S11 Fused
- Pin 87a: grounds to seat belt warning light (br/wh)

27: Combination (headlight) relay
- Pin F: to S2 Hot
- Pin 56: to headlight switch pin 56
- Pin 56a: to S4 Hot
- Pin S: to steering column pin S

50: Headlight relays (next to the headlight buckets):
- Pin 87: from S12 fused (this should be the only wired on the fused side of S12)

The S8 fused side leads to the cigarette lighter (among other things) which can be used to identify whether or not you have the correct bundle of wires on that fuse.

Note about the fresh air fan relay:
a better name for this would be the "load reduction relay," because it is used to power all the items that need to be switched off when the starter is cranking. The difference between circuit 15 (switched power) and circuit X (load reduction) is that the X position in the ignition switch temporarily disconnects the headlights and the fresh air fan relay when in the cranking position.

Also: this is for a 1972, you may need to make similar notes if you have to go though this exercise on another model year. Contrary to some comments found in old threads in this forum, the wiring diagrams are 100% accurate and you just need to learn how to read them. If a wire shown on the diagram stops suddenly with a number, it means that line is continued on another page (look for the same number next to the same colour).

Gord

[tjgalvin]

A follow-up to this, in case it will help anyone else:

I spent a couple of hours going though the fuse panel and relays with a continuity tester, and was able to put things back in order. Here are the notes I made to sort out the relay connections with respect to the fuse panel:

51: Horn relay
- Pin 30: from S11 Hot (red)
- Pin 85: to steering column pin S- (brown/white)
- Pin 86: from S8 Hot (red/white)
- Pin 87: to horn (black/yellow)
- Pin 87a: nil

54: Fresh air fan relay (load reduction relay)
- Pin 30: from S12 Hot (red)
- Pin 85: to ground (brown)
- Pin 86: from X (headlight switch and ignition) (red/white)
- Pin 87: to S8 Hot (black/red)
- Pin 87a: nil

53: Fog light relay
- Pin 30: from S10 Fused
- Pin 85: to S1 Hot
- Pin 86: to fog light switch pin K
- Pin 87: to fog lights pin 56a
- Pin 87a: nil

66: Buzzer
- Pin 86: from S11 Fused
- Pin 87a: grounds to seat belt warning light (br/wh)

27: Combination (headlight) relay
- Pin F: to S2 Hot
- Pin 56: to headlight switch pin 56
- Pin 56a: to S4 Hot
- Pin S: to steering column pin S

50: Headlight relays (next to the headlight buckets):
- Pin 87: from S12 fused (this should be the only wired on the fused side of S12)

The S8 fused side leads to the cigarette lighter (among other things) which can be used to identify whether or not you have the correct bundle of wires on that fuse.

Note about the fresh air fan relay:
a better name for this would be the "load reduction relay," because it is used to power all the items that need to be switched off when the starter is cranking. The difference between circuit 15 (switched power) and circuit X (load reduction) is that the X position in the ignition switch temporarily disconnects the headlights and the fresh air fan relay when in the cranking position.

Also: this is for a 1972, you may need to make similar notes if you have to go though this exercise on another model year. Contrary to some comments found in old threads in this forum, the wiring diagrams are 100% accurate and you just need to learn how to read them. If a wire shown on the diagram stops suddenly with a number, it means that line is continued on another page (look for the same number next to the same colour).

Gord

Gord,

Thanks for an enlightening entry. I am trying to determine if my blower motor is bad. From your experiments, I should be able to ground one of the blower WH wires and it should operate with the ignition in the ON position. It does not run.

So, if the relay is highly defetive, it could prevent operation. Or if S8 has failed, it would not work and neither would the lighter.

Do you think my logic is sound?

Tim

[mgphoto]

A follow-up to this, in case it will help anyone else:

I spent a couple of hours going though the fuse panel and relays with a continuity tester, and was able to put things back in order. Here are the notes I made to sort out the relay connections with respect to the fuse panel:

51: Horn relay
- Pin 30: from S11 Hot (red)
- Pin 85: to steering column pin S- (brown/white)
- Pin 86: from S8 Hot (red/white)
- Pin 87: to horn (black/yellow)
- Pin 87a: nil

54: Fresh air fan relay (load reduction relay)
- Pin 30: from S12 Hot (red)
- Pin 85: to ground (brown)
- Pin 86: from X (headlight switch and ignition) (red/white)
- Pin 87: to S8 Hot (black/red)
- Pin 87a: nil

53: Fog light relay
- Pin 30: from S10 Fused
- Pin 85: to S1 Hot
- Pin 86: to fog light switch pin K
- Pin 87: to fog lights pin 56a
- Pin 87a: nil

66: Buzzer
- Pin 86: from S11 Fused
- Pin 87a: grounds to seat belt warning light (br/wh)

27: Combination (headlight) relay
- Pin F: to S2 Hot
- Pin 56: to headlight switch pin 56
- Pin 56a: to S4 Hot
- Pin S: to steering column pin S

50: Headlight relays (next to the headlight buckets):
- Pin 87: from S12 fused (this should be the only wired on the fused side of S12)

The S8 fused side leads to the cigarette lighter (among other things) which can be used to identify whether or not you have the correct bundle of wires on that fuse.

Note about the fresh air fan relay:
a better name for this would be the "load reduction relay," because it is used to power all the items that need to be switched off when the starter is cranking. The difference between circuit 15 (switched power) and circuit X (load reduction) is that the X position in the ignition switch temporarily disconnects the headlights and the fresh air fan relay when in the cranking position.

Also: this is for a 1972, you may need to make similar notes if you have to go though this exercise on another model year. Contrary to some comments found in old threads in this forum, the wiring diagrams are 100% accurate and you just need to learn how to read them. If a wire shown on the diagram stops suddenly with a number, it means that line is continued on another page (look for the same number next to the same colour).

Gord

Gord,

Thanks for an enlightening entry. I am trying to determine if my blower motor is bad. From your experiments, I should be able to ground one of the blower WH wires and it should operate with the ignition in the ON position. It does not run.

So, if the relay is highly defetive, it could prevent operation. Or if S8 has failed, it would not work and neither would the lighter.

Do you think my logic is sound?

Tim

The blower motor could be stuck, mine had some leaves stopping in from running.

[Rob-O]

(IMG:style_emoticons/default/agree.gif) VERY common. Especially if the plastic grid is no longer (or never was) beneath the intake air slats on the outside cowl in front of the windshield.