Service slants

Motor, Jun 1999 by Juran, Ken

Ford Truck

No blower motor operation. Ford reports that some 1992-93 Econolines whose blower motor switch keeps burning out may need a Blower Motor Switch Relay Kit (Part No. F6UZ14A303-AB) to reduce the amount of current passing through the switch.

Here's a rundown of the details necessary to install the kit (refer to the illustration below).

Steps 1, 2 and 3: After disconnecting the battery, open the 12A581 wiring harness at the takeout to the washer pump/blower motor/blower motor resistor and find the orange/black splice (S148) with three 12-gauge circuits connected. Open the heat-shrink wrap and add the 18-gauge orange/black wire from the kits relay jumper to this splice (total of four wires spliced together). Then route the newly installed wire along the outside of the large wire harness loom that's attached to the firewall. You'll end up near the brake master cylinder.

Once there, open the 12A581 harness at the cowl between the two 76-pin takeouts. Find the 12-gauge orange/black circuit and cut it. Take the end of this wire that continues on toward the drivers side of the truck and splice it to the 18-gauge orange/black wire you just routed over from S148. (Tape off the other end of the cut wire that continues back toward the passenger side of the vehicle.)

Now move to the outboard side of the 76-pin takeouts, find the 18-gauge yellow/red circuit in the loom and cut it as well. Then splice the two ends with the 18-gauge yellow/red wire (ending up with a three-wire splice) from the kits relay jumper.

Steps 4 and 5: Take the 10-gauge black wire from the kit's relay jumper and attach it to the ground screw on the driver's-side radiator support near the headlight opening. Snap the kit's relay onto one of the open fingers on the four-finger relay bracket near the headlight opening.

Finally, tape all exposed wiring to the outside of the wiring looms. Replace the blower motor switch and fix any other damaged wiring, as necessary.

GM

ETS OFF light stays on, hot-soak rpm sag, scan tool communication corrupted. The customer will notice the first t\vo problems and you may notice the third while trying to diagnose the others on a 1995 Buick Skylark, Oldsmobile Achieva or Pontiac Grand Am all with the 3100 V6 (VIN M).

There's an Enhanced Traction System indicator light on the instrument panel that's supposed to be out whenever the traction control is engaged and functioning normally. But your customer may come in with the car and complain that the ETS OFF light is always illuminated, and he'll want you to get it to go out. He'll also want you to look into this small hesitation that he feels after a 45-minute hot soak restart with the a/c on. Luckily, all of these problems can be fixed simultaneously.

You see, when you plug in your aftermarket scan tool (GM calls it a nonGM Techline SAE J1978 OBD II scan tool) to try and find a clue for the first two problems, it may not communicate with the PCM when in "Current," "Freeze Frame" or "Test Parameters and Results" mode.

So get the car to a dealer and have the PROM reprogrammed with Calibration No. 16238674. It will correct the three glitches. With the old parameters, the ETS was programmed to go out if certain DTCs ever set in the system. The "hesitation" the customer feels is actually an rpm sag caused by a bad engine control algorithm in the software. And the scan tool noncommunication was a software/calibration anomaly, says GM.

By the way, if you happen to be working on a vehicle that's been exported across the border without OBD II and runs on unleaded, the new calibration number is 16238684.

Chrysler

Ripped air filter. There may be some 1995-96 Cirrus/Stratus models and some 1996 Sebrings out there built before 9/15/95 that still have their original factory air filter in place. In addition to the filter probably being completely clogged bv now, it may also have a tear in the corner of the lower sealing side on the forward or rearward edge of the urethane seal. So this opening may have been letting grit get into the engine for years.

Chrysler switched to an updated filter (Part No. 4873153) late in 1995, but there's no telling how many of the ripped ones are still out there. Be on the lookout, for your customers sake.

Nissan

Deleted timing chain guides. According to the Automotive Engine Rebuilders Association (AERA), Nissan eliminated two timing chain guides on its 1991-93 1.6-liter DOHC engines, beginning with engines produced in March 1993. The ones that got nixed were the top and left-side guides. To boot, all replacement cylinder heads (Part No. 11040-57Y1) come through without the drilled holes necessary to attach the guides.

The bottom line is that these two guides make noise and are not really necessary for proper chain operation. So Nissan's recommendation is to eliminate the top and left-side guides anytime cylinder head repair is performed.

Infiniti

Poor a/c performance. Here is Infiniti's procedure for diagnosing a complaint of poor a/c in a 1990-94 Q45. The key point to remember is that the automatic climate control system is divided into hvo subsystems of temperature control and refrigerant that need to be isolated and tested separately. Then, make sure you understand the customer's complaint completely