I'm about to lose it! '87 w/4.3L & AC/Htr. Blower motor won't run (lost this function on Tuesday morning without warning). Prior to no blower action, motor did make a whining noise until it warmed up.

I have replaced the 25A fuse (twice! The first fuse I replaced looked OK, i.e. no break in the wire), installed a new blower speed switch in the control head, AND replaced the original blower motor. I have also cleaned up the ground lug which is held to the mounting plate with a sheet metal screw, as well as cleaned up the terminals on the resistor block mounted in the top of the AC plenum, but still no action.

I have a new blower relay yet to install this morning and may try another fuse, but from reading the '86 and '87 Shop Manuals it would seem that the blower should be running even if the relay is bad (?).

The '86 Manual shows a fusible link in the system near the starter (?), which I have not checked. Would this link also affect other items in the electrical system?

What am I overlooking? Should I also replace the resistor block? Do I need to check the fusible link, and where is it? What do I look for? What checks should I do with a trouble light/multimeter? I'm running out of things to replace and I need to blow warm air.

When it comes to electrical, I confess that I am a novice (heck, I don't even know how to work a multitester in order to check voltage).

Additional info to my original posting. I just replaced the relay and fuse - no luck, no blower at any switch setting. It also appears there are no broken resistor wires, but I didn't put a multimeter across them to check continuity.

I also noticed (probably a key thing here) that the AC clutch does not kick in when the selector lever is moved into the three AC positions. Is there something in the vacuum system that is connected with the electrical to keep the blower from coming on? Does this mean I need to replace the mode selector switch ('86 shop manual pages 8A-63-pages 0 through 8), and if so can a new one be readliy obtained from the local Chevy dealer?

Is there anything in the vacuum system that I should be looking out for as well? I did notice a violet wire going to a vacuum check valve, and that the rubber hose was showing surface cracking. Would a bad vacuum hose create a chain reaction that would keep the AC clutch and blower motor from operating?

In reviewing the '87 Shop Manual pg 1B-19 it does mention that there is another fuse for the high speed blower circuit "in the electrical wiring between the junction terminal and the air conditioner relay." What should I be looking for here, or is this even the culprit?

BTW, the '87 Shop Manual is a JOKE when it comes to diagramming the system (glad I got the '86 version as well - much better descriptions).

Read this post Here (http://elcaminocentral.com/postt676.html)

Mucho Gracias! The brown wire's connector was the culprit. I had to pull the center dash cover/bezel, heater control head and, in order to get better access, pulled the radio as well as disconnect the fan switch and vacuum control connectors. The plug was tucked behind the dash toward the passenger side and didn't have a lot of slack to pull out through the center dash opening. It was difficult to separate as the inside was melted. I scraped the exposed male plug's metal contacts with a utility knife and dental pick, took a dental pick to scrape out the female plug, reconnected it and the other connectors, and voila! Blower runs. AC compressor kicks in as it's supposed to.

BTW, while probing around in the engine bay, I noticed that several of the original vacuum hoses were cracked, split, etc. Since I've replaced virtually everything else with the heater system, it made sense to replace the 5/32" and 7/32" hoses from the check valve off the violet wire to the vacuum cannisters behind the left headlight assembly, and the hose from the check valve to the intake manifold nipple.

BTW, the '87 Shop Manual is a JOKE when it comes to diagramming the system (glad I got the '86 version as well - much better descriptions).
The 86 Helm El Camino Shop Manual includes the electrical diagnostics section. The 87 Helm Shop Manual did not. There is a separate 87 Electrical Supplement manual that has the electrical diagnostics in it.

From what you've described it sounds like the problem is either the A/C Control head mode selector switch, or the blower switch. First, jumper 12V from the battery to the purple wire on the blower motor. If the motor runs then the motor and it's ground are OK. Now it's time to get out the multimeter and do some voltage checks.

With the ignition on, check between ground and the brown wire on the mode selector switch. That's the 12V feed into the switch. If 12V is present turn the mode selector switch to any position besides "OFF" and check between ground and the brown/white wire on the mode selector switch. This is the 12V out of the mode selector switch going to the blower switch. If 12V is present then the mode selector switch is OK. Next, to test the blower switch and the blower resistor, hook up the multimeter to the dark blue wire on the blower relay. When you switch the blower switch to Speed 1 or Speed 2 you should see something less than 12V on the meter. Speed 2 voltage should be higher than Speed 1. The High switch position should bring 12V to the orange wire on the blower switch.

The fusable link is for high speed operation only.

Let us know how you make out.

Alan, noticed your sig..have a question:
I have a customer 57 Bird in my shop as we speak, and need to find someone who can convert the old mechanical cable driven tach to electric.
Know of any company that does this?

Thanks,
Robert