20 Most Recent 1991 Cadillac DeVille - Page 4 Questions & Answers

you need to do a load test on the battery first to verify its good,charge battery fully,turn headlights on high beam,wait for five min and crank engine with lights on,see if you still have a good cranking time,if you don't replace battery,if you do charge battery up to full again,check voltage at battery post with a multi meter,
should be 13 volts at minimal,now turn headlights on ,heater on,and flasher on and pull in gear,have a friend check voltage at battery to see if it is staying above 12.50 volts,if it is below 12.50 the alternator is not putting out on a load,replace it.if these check out good,check for dome or hood or trunk light not shutting off ,or something else draining battery.

You'll need a special tool to release the tension on the belt. Once you have that , apply pressure on the bar to move tensioner enough to slide the belt off.

you can get that info from dealer with last eight of vin

USUALLY P/S PUMP

the clip is broken you can get new ones at almost any parts store they're like $5 for a pack of them although typically a pain to get to I’m happy to assist further over the phone at https://www.6ya.com/expert/brock_d67526d2a834c47e

change the sensor. 91 its lasted a long time. if light still on after the change come back and report it

The ecm,the last didget can't be under no more than 2 didgets or over 2 didgets if so the ecm is program for different sensors

Have you tried jump starting the vehicle, if so and still would'nt check the wires on the start make sure none are broke or loose

Has the engine been tuned up recently? If not, have a thorough tuneup performed. If it has, try purchasing a can of Seafoam fuel additive and pour the can into a full tank of gas. You may see some smokoe from the exhaust as you drive, but that's just the Seafoam doing its job - correcting the adverse effects of ethanol in the gasoline we're forced to buy these days.

my question for u does it start when u jump it? if yes you have a bad battery
if it clicks with jumper cables too then you probley have a bad starter

Well I was going to say it sounds like a faulty transmission speed sensor, but the headlight circuit would not affect that.Could be a short somewhere in the harness for the instrument cluster.

Need to look at a wiring diagram to see what controls itI had a 1986 Caddy that had that problemIt had a module for the blower & A/C compressor control in one part.Google the question

car will relearn in about 30 min when u connect batt back--will be rough for a while

Trouble Code #26 means "Idle Speed Control (ISC) motor/throttle switch circuit fault (short)

Are you getting a trouble code for the sensor ?