Most likely has a leak somewhere in the line, or the switch in the parking brake petal is bad.
my switch went bad, just removed the bulb, cheap fix
behind the panel,next to the parking brake.
The PCM for the 89 Bronco is located on the firewall on the driver side. You can access it from inside the cab, behind the parking brake pedal.
bad gasket
idle air control valve?
Could be gas in the oil causing low or no compression.
Bronco Buster - 1935 was released on: USA: 5 August 1935
Bronco Billy - 2013 was released on: USA: 1 September 2013
Bronco Roads - 2011 was released on: USA: 1 April 2012
No, the front end of 92 - 96 Broncos is completely different than 87 - 91 Broncos.
Bronco - 1958 The Soft Answer - 2.4 was released on: USA: 3 November 1959
Bronco Roads - 2011 Roughin' It 2-19 was released on: USA: 2013
Bronco - 1958 The Buckbrier Trail - 3.6 was released on: USA:20 February 1961