Thar she blows! (HVAC blower night & day.)

[BullnoseLuvr]

Apologies if that came across the wrong way. That thread just has the diagrams in it and discussion to go with.

The voltage test (Gary can confirm/deny this is where he measured his drop) should be done at the blower motor connector C603 connecting the positive wire there with the battery ground. That's as close as you can get to the motor as well as the most logical place (both in effectiveness and accessibility) to insert the relay.

Is that what you are asking?

NP. And yep exactly. It would make sense to get the voltage drop in whatever is determined to be the origin of the hot side of the HVAC wiring (which could be debatable I suppose, but apples to apples it wouldn't really matter in determining the improvement of the relay mod) and not all the way back to the battery. But I'm still curious. I'm only getting about 10 volts at the backup lights which is keeping me up at night.

Mark

[ArdWrknTrk]

Now, if you'd just go measure Scott's or Jim's air flow with their relay mod's we'd know how much improvement they make. Of course, that's assuming their evap's aren't clogged.

Unfortunately I don't have an anemometer,(or an evaporator, for that matter) but it would be easy enough to bypass the relays to get a sense of how much a bit of fan speed relates to velocity out the vents.

My '87 has a she different dash, so it might not be direct to a Bullnose, but it would validate the efficacy of the relay mod (or not).

I really want to see the TSB that accompanies the '87-'91 E350 relay kit I've installed.

[Gary Lewis]

Unfortunately I don't have an anemometer,(or an evaporator, for that matter) but it would be easy enough to bypass the relays to get a sense of how much a bit of fan speed relates to velocity out the vents.

My '87 has a she different dash, so it might not be direct to a Bullnose, but it would validate the efficacy of the relay mod (or not).

I really want to see the TSB that accompanies the '87-'91 E350 relay kit I've installed.

Jim - My relay kit is to be here any day, and hopefully there will be a clue or two that will let me find that TSB in the many, MANY books I have.

[Gary Lewis]

Apologies if that came across the wrong way. That thread just has the diagrams in it and discussion to go with.

The voltage test (Gary can confirm/deny this is where he measured his drop) should be done at the blower motor connector C603 connecting the positive wire there with the battery ground. That's as close as you can get to the motor as well as the most logical place (both in effectiveness and accessibility) to insert the relay.

Is that what you are asking?

NP. And yep exactly. It would make sense to get the voltage drop in whatever is determined to be the origin of the hot side of the HVAC wiring (which could be debatable I suppose, but apples to apples it wouldn't really matter in determining the improvement of the relay mod) and not all the way back to the battery. But I'm still curious. I'm only getting about 10 volts at the backup lights which is keeping me up at night.

Mark

Yes, Scott, I measure my drop from the battery's positive post to the motor's positive lead at the connector. And similarly I measure the the return side drop from that connector to the battery's negative post. Obviously that's best case and a relay won't quite have that much effect, but it'll come close.

[ArdWrknTrk]

Jim - My relay kit is to be here any day, and hopefully there will be a clue or two that will let me find that TSB in the many, MANY books I have.

Mine came in simple plastic bags (exactly the one shown)

There were no instructions, or even a release date.

But obviously if we had a date, we could find the TSB...

[FuzzFace2]

And I disagree with Dave that regular cabs don't need more flow. Big Blue's A/C had to run on High most of the time, and it was supposedly fully charged. Yes, the evaporator was partially clogged, but not badly.

I am using the factory evap that I cleaned out hand fulls of junk then took my 175 psi shop air and blew it out. Should have seen the mess inside the cab and I am still getting a little now and then.

If I knew it could have been that bad I would have pulled it out and washed it with water before I installed the HVAC box.

My system is fully charged or some may say over charged but when it is 90*+ out I don't need to run the fan on high all the time.

I should also point out that I have a hot water cut off valve so when on MAX AC there is no hot water going to the heater core. In the mornings to get the humidity down I run the AC on normal, fan on low and turn the temp up a little or it gets to cold OAT of about 78*-83* at 2am.

Then again it could be I am out in the heat working so when it cools down it feels good where others may still feel its to hot

Wonder if HF has one of them air meters?

Dave ----

 

[Gary Lewis]

Mine came in simple plastic bags (exactly the one shown)

There were no instructions, or even a release date.

But obviously if we had a date, we could find the TSB...

The relay kit came in, and there's precious little info on it, just like you said. May just have to go looking for the TSB.

Any guess on dates?

[ArdWrknTrk]

The relay kit came in, and there's precious little info on it, just like you said. May just have to go looking for the TSB.

Any guess on dates?

The listing makes it seem like it was for vans during our Bricknose era.

But it all depends on when Ford decided to acknowledge the problem and provide dealerships with a solution.

[Gary Lewis]

The listing makes it seem like it was for vans during our Bricknose era.

But it all depends on when Ford decided to acknowledge the problem and provide dealerships with a solution.

I'll see what I can find.....

[kramttocs]

Wonder if HF has one of them air meters?

Dave ----

I didn't see one online but did see this fuse buddy knockoff tester

Nothing a multimeter can't do and doesn't help with the vent airflow test but still looks convenient in some situations.