88 Bronco II Questions

My son just bought his first car, an '88 Bronco II Eddie Bauer, 5spd. Runs smooth, drives pretty well, except for the one 205/75 and three 235/75's!:rofl: Interior is in very good condition, except both armrests/door pulls are bad. Power windows, locks, power lumbar all work. Body is in fair shape; some bonehead repainted without masking anything off, and LOTS of drips! A fair amount of rust too, the worst spot being under the rt tail light. But, for $600, its a great deal for him, and he will learn alot working on it. We'll be repainting it next Summer, so he'll have plenty of time to get rid of all the small spots of surface rust!

We have a few issues with it:

No low-beams - thought it was the lamps since I had 12v to high and low, but as soon as a lamp is plugged in, no power. I'm figuring dimmer/signal switch. High beams work fine. Seems like it shorts when there is a current draw through the switch.

High idle - almost seems like a vac leak 'cause it takes a while to cycle down to 1100, as low as I can get it, even with the idle adjustment backed all the way down. I sprayed carb cleaner around and had no change in idle speed. I unplugged the IAC and the idle dropped. I'm assuming its the IAC, mounted to the pass side of the air plenum?

Temp gauge not working - I found a 2-wire harness coming from the engine not plugged into anything, and I found nothing to plug it into. The PO said the engine had around 70K on it, I'm wondering if someone swapped it for a 89 or 90, maybe diff connectors??

Thanks for any input!!

My son just bought his first car, an '88 Bronco II Eddie Bauer, 5spd. Runs smooth, drives pretty well, except for the one 205/75 and three 235/75's!:rofl: Interior is in very good condition, except both armrests/door pulls are bad. Power windows, locks, power lumbar all work. Body is in fair shape; some bonehead repainted without masking anything off, and LOTS of drips! A fair amount of rust too, the worst spot being under the rt tail light. But, for $600, its a great deal for him, and he will learn alot working on it. We'll be repainting it next Summer, so he'll have plenty of time to get rid of all the small spots of surface rust!

We have a few issues with it:

No low-beams - thought it was the lamps since I had 12v to high and low, but as soon as a lamp is plugged in, no power. I'm figuring dimmer/signal switch. High beams work fine. Seems like it shorts when there is a current draw through the switch.

High idle - almost seems like a vac leak 'cause it takes a while to cycle down to 1100, as low as I can get it, even with the idle adjustment backed all the way down. I sprayed carb cleaner around and had no change in idle speed. I unplugged the IAC and the idle dropped. I'm assuming its the IAC, mounted to the pass side of the air plenum?

Temp gauge not working - I found a 2-wire harness coming from the engine not plugged into anything, and I found nothing to plug it into. The PO said the engine had around 70K on it, I'm wondering if someone swapped it for a 89 or 90, maybe diff connectors??

Thanks for any input!!


Traced the connected end of the 2-wire harness to the pass side, into a larger harness that had the a/c pressure switch connector, found an empty socket on the a/c compressor. Also found the temp sensor wire hidden within the huge wad of wires across the engine.

Still can't get a normal idle. Reset the TPS to 0.95v, pulled and cleaned the IAC. If I unplug the IAC while at idle, the idle drops to a normal idle. With the IAC plugged in, the idle is pretty stable @ 1100-or-so, after finally settling down from 1500-2K.
Any ideas?