jimbo486

Jim,

My A/C quit working some time ago. In fact, if you recall I noticed it the night I met you when you came out to that truck meet. Could this dip-switch going bad be the problem I have also?

whosdunit

JIM,by coming straight from the batt., does this take primary load off of our weak fuse panel? Also i ordered the Bosch relay w/ dioded ,does it wire the same way as your drawing?

Jim Lane

Jimbo,
Very possible, when mine was getting flakey I could smack the cycling switch and it would start working again for a short time.

It finally gave up by the I-15 freeway headed to nowhere in 100+ temperatures, this is when I threw together this relay circuit in Home Depot parking lot.

BTW "DIP" is an acronym for Dual Inline Package like an integrated circuit.

Jim Lane

Yes, it takes the clutch coil load off the fuse panel so make sure you include a fuse in the battery feed.

Also i ordered the Bosch relay w/ dioded ,does it wire the same way as your drawing?

Coil polarity is important, If you use a relay with an internal quench diode you want Term.#86 connected to the (+) supply.




Jim

johnny08

Could someone please post a diagram of the rest of the A/C circuit? I have no power at my AC clutch. from what i understand thus far, I should always have power to the A/c clutch when the ignition is on and the ground is switched. Im wondering if this mod will fix my a/c.

I have Ck the low pressure cut off and its good. I'm wondering how the rest of my circuit will be with this relay mod.

I'm not low on freon.
Also i have no power to my wipers?
91.5 ic d250

johnny08

I just checked the continuity from the blue/striped wire. Found out this goes from there through the both switch on control and low press switch to ground.

Im most certain this mod will fix my a/c. Still not sure why my wipers are dead.

whosdunit

ck. the wiper fuse it proble blew when you touched the brn., wire.to the dk/blue.

Jim5870

Would having the cycling switch by-passed
affect the re-charging process?

johnny08

Thanks... I found the problem the fuse was good... but someone cut the wire to the fuse box.

Jim Lane

When you recharge your air conditioned you might have to jumper the low pressure cutout switch mounted on the H-valve to start the compressor if the static pressure is too low in the system.

Jumper the 2 pins using an opened paper clip to start the compressor.

You will have to do this even if the cycling switch had not been modified with my circuit.

Jim

Barney428

Made this repair to my 91 this evening. Thanks for some great information.

johnny08

My 91 has much cooler ac now. Im gonna do both trucks .. I also cleane. d out the hvac intake and used some coil cleaner on the evaporator.

Jim5870

I pulled out the temp probe in my trucks and man is it cold in there now!

TJE

How far did you pull it out? Did you wrap it in that A/C tape?

Thanks, Tony

Jim5870

I pulled it all the way out, might put it back in a little.

Its so cold that I have to run the blower on low