Top 10 1988 Chevrolet C1500 Questions & Answers

I had the same problem. My backup lights wouldn't come on in when I put the auto. trans. shifter into the Reverse position. They WOULD come on briefly as I moved the shifter from Park position into Reverse, but would go off again when the shifter reached the Reverse detent. I got the solution from the Haynes service manual, in which the relevant switch is referred to as something like the neutral safety switch. Check on top of the steering column close to the firewall. Set the parking brake, then move the auto. trans. shifter into Neutral position. Get under the dash and rotate the neutral safety switch clockwise as far as it will go. Then move the shifter into the Park position, and your switch should be set. If the backup lights don't come on now when the shifter is put into Reverse position with the ignition switch 'on', there may be another problem.

700R4/2004R TV Cable Adjustment Instructions WARNING! IMPORTANT NOTICE!
POST INSTALLATION ADJUSTMENT. It is imperative that after your new TCI® 700R4/2004R transmission has been installed that the Throttle Valve (TV) Cable gets adjusted properly, DAMAGE WILL OCCUR to the transmission, voiding the warranty. If you are unsure about the proper adjustment needed, call TCI®'s tech line for help or refer to a General Motors service manual for additional information and reference.
Function of the TV Cable: Many people believe that this is a detent downshift cable and that this is the only function that the cable performs. In actuality, the TV Cable controls line pressures, shift points, part throttle downshifts and detent downshifts. The cable functions similarly to the combination vacuum modulator/cable systems found on other automatic transmissions.
TV Cable Connection: If you are retrofitting your TCI® 700R4/2004R transmission in place of a different model transmission (i.e. TH-350 or TH-400) it is imperative that you follow the TV Cable bracket fabrication instructions. If your TCI® 700R4/2004R is replacing an original 700R4/2004R then skip to Step 2.
Step 1 Obtain a cable that is designed for use with the 700R4/2004R transmission. The TH-350 and older TH-200 cables are designed differently and will not work. A salvage yard cable may work but be forewarned: There are about 30 different length cables found on stock vehicles and a cable that is too short in your application will not work. Also, used cables could have a number of problems as well, including stretched cables, damaged sheathing or housings or mutilated cable ends. TCI® recommends our universal TV Cable (TCI® 376800) that is designed to work correctly in any 700R4/2004R application.
Step 2 With the carburetor/throttle body end of the TV Cable disconnected, pull the link out of the transmission and fit the cable end to the link as shown in Figure 1. Push the TV Cable sheath into the seal in the transmission and tighten the 10mm retaining bolt. If your vehicle has a factory installed bracket for the TV Cable then skip to Step 4.
Step 3 Install a bracket that will allow the TV Cable to mount to the carburetor/throttle body. TCI® carries two brackets: TCI® 376700 works with Rochester Quadrajets, Carter AFBs or Edelbrock Performer carburetors. TCI® 376800 works with most Holley carburetors.
If you are using a Chevrolet TBI/TPI induction system, then correct brackets can be obtained from a salvage yard or a local car dealership.
Figure 2 demonstrates the correct geometry for the TV Cable mounting position. Use the following procedure to determine if your ADJUSTER MOUNTING POINT is correct.
a. Push in the Adjust Tab and retract the Slider in the direction shown in Figure 3.
b. Without allowing the Slider to move, pull the cable until it stops and measure from the mounting bracket to the cable end. Add 3/16" to this measurement and that will determine the ADJUSTER MOUNTING POINT distance at full throttle (WOT).
c. Also note in Figure 2 that the distance from the throttle shaft to the cable end is referenced. This distance must be between 1 7/64" and 1 1/8"! The cable end mounting point should follow a 78° arc between closed throttle and WOT in order to achieve the proper amount of pull on the cable.
Step 4 Adjustment of the TV Cable on a gasoline engine. For a diesel application go to Step 5.
a. Adjustments are made with the engine off. Locate the Adjust Tab on the cable housing. Press in the tab and push the slider as shown in Figure 3.
b. Release the tab and rotate the throttle lever to WOT and the cable will self adjust itself as evidenced by a few audible clicks. Release the throttle lever and check the cable for any signs of binding or sticking.
c. Road test the vehicle. Under moderate acceleration your shift points should be close to the following:
1-2…………………15-20 MPH
2-3…………………25-30 MPH
3-4…………………40-45 MPH
If the cable is adjusted too loosely your transmission will exhibit soft, stacked shifts (not spread out). DO NOT CONTINUE DRIVING VEHICLE IF THIS HAPPENS! Immediately readjust cable. If you continue to have problems, please contact TCI®'s tech department for assistance.
Step 5 Adjustments of the TV Cable on a diesel engine.
a. Adjustments are made with the engine off. If equipped with cruise control, remove the control rod.
b. Disconnect the TV Cable end from the throttle lever.
c. Loosen the locknut on the pump rod and shorten several turns.
d. Turn throttle lever to WOT and tighten the pump rod locknut.
e. Lengthen pump rod until injection pump lever contacts the full throttle stop.
f. Release the throttle lever and tighten the pump rod locknut.
g. Remove pump rod from the throttle lever.
h. Reconnect the TV Cable end to the throttle lever.
i. Press in the Adjust Tab and move Slider as shown in Figure 3.
j. Release the tab and rotate the throttle lever to WOT and the cable will self adjust itself as evidenced by a few audible clicks. Release the throttle lever and check the cable for any signs of binding or sticking.
k. Reconnect the pump rod and cruise control throttle rod, if equipped.
l. If equipped with cruise control, adjust servo throttle rod to minimum slack.
m. Road test the vehicle. Under moderate acceleration your shift points should be close to the following:
1-2…………………15-20 MPH
2-3…………………25-30 MPH
3-4…………………40-45 MPH
n. If the cable is adjusted too loosely your transmission will exhibit soft, stacked shifts (not spread out). DO NOT CONTINUE DRIVING VEHICLE IF THIS HAPPENS! Immediately readjust cable. If you continue to have problems, please contact TCI®'s tech department for assistance.

GAP=0.035" source: rockauto.com

Ok the BRAKE BOOSTER is ONLY there to give you pwer assisted, otherwise NO POWER BRAKES. ( not anything to do with the low brake pedal ) Hopefully the junkyard master cylinder was in better shape than your original. AS far a bleedinda system, heres what I do. First with a1998 vehicle, I would go to ALL 4 wheels , OPEN & CLOSE slightly each bleeder to insure none of them are FROZEN, and they do freeze shut ENSUE THE MASTER CYLINDER IS FULL and CLOSED Now with an assistant sitting in the drivers seat, ready to pump the brakes, and ABLE TO HEAR YOU. Go to the furthest wheel from the master which would be the R/R. DONT touch anything yet. Tell the asst too slowly pump the brake pedal till it gets hard, and then HOLD THE PEDAL DOWN ( and dont let up on it until the pedal drops. If the ast lets up before the bleeder is closed you **** in air.Repeat at each wheel til the pedal stays hard. Hope this helps

I personally have 1988 GMC truck and had to replace the fuel pump. I found all the info including wiring diagram in a haynes repair manual. These can be purchased in most automotive parts stores. Something I found interesting is that the fuel pump's operation works through the oil pressure switch, located by the distributor screwed into the engine block. If this switch is stuck or sticking it will affect the fuel pump. Replaced a good fuel pump for nothing! The truck had sit up for awhile and the ground wire connections had to be cleaned as well.

1988 chevy r 3500 1 ton changed out driver front brake caliper
brakes are soft peddle goes to the floor tried to bleed but no brake fluid will come please help

Hi my name is Tom and I am here to help.

aaah!! the wonderful chevy 350. Probably the best engine ever made. It has had a track record few other engines can match.

Enough of old school. Unless they have moved the sensor in the last 30 years, you should find the sensor below the head 1/2 way to the oil pan.

Remove the electrical connection on the top and using the proper open ended wrench unscrew the sensor. Replace with new sensor and reattached the wire and you are home free.

If I forgot something or I can be of further help feel free to call or email me. Either way, please rank my advice so I can become a better helper in the future.

TomE(414-475-5968)

The water that goes thru the heater core is controlled by a simple mechanical flap valve. That valve is controlled with a vacuum by the temperature knob on the dash: more you turn it toward heat/red - more the valve is opened.
In your case the valve isn't opening so you must replace it. here it is
http://www.autopartswarehouse.com/search/?searchType=refined&Nr=&N=0&Ntt=HEATER+VALVE

You need to retreive the trouble code stored in the computer.

ON YOUR FIREWALL (CLOSE TO THE WINDSHIELD)