First, make sure the small orange wire at the resistor/relay has battery voltage with the key on, mode switch on heat, and the blower switch in the high position.
How to bypass the OEM high blower relay
You’ll need a relay, some 14 gauge wire, a few terminals, a soldering gun, rosin core solder, electrical tape, and about 15 minutes of time.
Most auto parts stores carry the terminals, and relays that are rated at 40 amps that look similar to this for around $5 USD:
Mount the relay to a secure spot under the hood near the heater blower motor so that it will not interfere with anything. On the Astro Safari, there is a flat spot on the firewall just above the blower motor that works well. The terminals should be facing down so water will not enter the relay. There are 5 terminals on the relay, only 4 of them will be used to bypass the high blower relay.
To make the wire harness for the relay, you’ll need four 14 gauge pieces of wire about 18” long. On one end of each wire, solder on a female spade terminal.
On one of the 4 wires, solder an eyelet terminal on:
You should now have three 18” wires with a female spade terminal on one end of each wire. You should also have one 18” wire with a female spade terminal on one end, and an eyelet terminal on the other end.
Attach the eyelet terminal to body ground, near the relay, using a screw. Connect the other end to the relay terminal #86. There are 2 orange wires going to the original blower resistor/relay. Cut both of them close to the electrical connector. Using one of the 18” wires, solder it to the larger orange wire and connect it to relay terminal #30. Using another 18” wire, solder it to the smaller orange wire and connect it to relay terminal #85. Using the last 18” wire, connect it to relay terminal #87. At the blower motor there is a purple wire, don’t cut the wire, strip a section long enough to solder the wire from relay terminal #87.
Neatly tie up the wires so they don’t interfere with anything, and you’re done.
Any questions, just ask.