the hot side was left. the '1', you saw was being tested in the left. When i switched to ohms, left side, got the reading above.

 

I'm not being clear enough so let me try over.

When you pull the fuse, one socket should have battery voltage (approx 12V) and the other side should have zero voltage. You verified battery voltage at the fuse pin that should have "hot at all times" power. Thats good. Next we have to see why this power does not show up on pin 87 of the HVAC relay. You put one meter lead in the fuse socket that did not have power which I believe is what you call the "right" socket and then put the other meter lead in socket 87 of the HVAC relay. The meter should be on 200 ohms which means it will read resistance between zero and up to 200 ohms. If the reading is higher than 200 ohms then most meters will display a "1" to indicate out of range.

George

 

From the dead side of the fuse connector it read '1', continuity. For ohms it read 40.5. What does this mean, and what next?

 

That means that the connection from the fuse to the relay is marginal, it reads 40 ohms of resistance. That 3 foot run of wire through one connector should read a couple of ohms max. That means that you have corrosion, a loose connector, a frayed wire, etc. Your choices at this point are:

1) Live without fan speed #4

2) Create a fused wire "hack" from the battery to pin 87 on the relay to restore fused always on power to the hot side of the relay

3) Probing wires with needle probes or by scraping off some insulation to narrow down where the problem is. Either there is a problem under the fuse block, in the orange wire run or at either end where the relay and fuse connect. Be certain you really want this restored to original before doing this step full bore because you may need to unbolt and lift up the fuse block and if there is corrosion, more things may stop working.

Let me know what you want to do and I'll guide you through it.

George

 

I'd prefer to fix the problem appropriately. So it would be a 30 Amp fusible link from the battery?

Whatever I decide, it wont be completed today. Could you go into pulling the fuse block, please?

 

I would do a little more testing before tearing into anything.

Be sure that fuse is good. What is the ohm reading if you test it?

Put the fuse back in and verify no voltage at relay pin 87

With the blower speed set on anything except #4 probe both orange wires behind the relay socket and see if you get 12V on either wire.

If not then trace the orange wire that goes back to the U/H fuse block and look for anything that is hosed (broken, frayed, corrosion, etc).

When you know which orange wire it is, probe it right after it leaves the fuse block and see if you have 12V. If not then its in the fuse block or under the fuse block. If no power there also make sure that the fuse sockets are nice and tight and clean.

Iv'e never unbolted that fuse block on my truck so I'll have to go look tonight.

Fused power would be a proper gauge wire for that power level. 30A at under 10' would be 10 gauge, connected with a ring connector at the battery or any connector block soon after the battery with a fuse holder inline with the other end connected to the cut orange wire going into the relay and the other cut end taped off.

George

 

Ohms on the fuse is .1. first, I've been testing the relay by taking the cover off. Is this fine? With cover off I'm getting power to 87. I'm thoroughly confused. Still nothing on 4 at blower.

 

I was sitting in the car with it on 3, blowing, and for a second it stopped then restarted. I've had a bug somewhere. Sometimes when the truck has been sitting overnight usually it will start but the gauged are pinned at zero and I have dim lights. After a couple minutes everything comes to life.

 

That's a good reading on the fuse. Can you show me a pic of what you mean by taking the cover off of the relay?

George